206 research outputs found

    Response to comment on 'Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity'

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    Lambert et al. question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm that our study provides unambiguous evidence that chytridiomycosis has affected at least 501 amphibian species

    Spin Caloritronics

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    This is a brief overview of the state of the art of spin caloritronics, the science and technology of controlling heat currents by the electron spin degree of freedom (and vice versa).Comment: To be published in "Spin Current", edited by S. Maekawa, E. Saitoh, S. Valenzuela and Y. Kimura, Oxford University Pres

    Adaptive remodeling of the bacterial proteome by specific ribosomal modification regulates Pseudomonas infection and niche colonisation

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    Post-transcriptional control of protein abundance is a highly important, underexplored regulatory process by which organisms respond to their environments. Here we describe an important and previously unidentified regulatory pathway involving the ribosomal modification protein RimK, its regulator proteins RimA and RimB, and the widespread bacterial second messenger cyclic-di-GMP (cdG). Disruption of rimK affects motility and surface attachment in pathogenic and commensal Pseudomonas species, with rimK deletion significantly compromising rhizosphere colonisation by the commensal soil bacterium P. fluorescens, and plant infection by the pathogens P. syringae and P. aeruginosa. RimK functions as an ATP-dependent glutamyl ligase, adding glutamate residues to the C-terminus of ribosomal protein RpsF and inducing specific effects on both ribosome protein complement and function. Deletion of rimK in P. fluorescens leads to markedly reduced levels of multiple ribosomal proteins, and also of the key translational regulator Hfq. In turn, reduced Hfq levels induce specific downstream proteomic changes, with significant increases in multiple ABC transporters, stress response proteins and non-ribosomal peptide synthetases seen for both ΔrimK and Δhfq mutants. The activity of RimK is itself controlled by interactions with RimA, RimB and cdG. We propose that control of RimK activity represents a novel regulatory mechanism that dynamically influences interactions between bacteria and their hosts; translating environmental pressures into dynamic ribosomal changes, and consequently to an adaptive remodeling of the bacterial proteome

    Surface Hardness Impairment of Quorum Sensing and Swarming for Pseudomonas aeruginosa

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    The importance of rhamnolipid to swarming of the bacterium Pseudomonas aeruginosa is well established. It is frequently, but not exclusively, observed that P. aeruginosa swarms in tendril patterns—formation of these tendrils requires rhamnolipid. We were interested to explain the impact of surface changes on P. aeruginosa swarm tendril development. Here we report that P. aeruginosa quorum sensing and rhamnolipid production is impaired when growing on harder semi-solid surfaces. P. aeruginosa wild-type swarms showed huge variation in tendril formation with small deviations to the “standard” swarm agar concentration of 0.5%. These macroscopic differences correlated with microscopic investigation of cells close to the advancing swarm edge using fluorescent gene reporters. Tendril swarms showed significant rhlA-gfp reporter expression right up to the advancing edge of swarming cells while swarms without tendrils (grown on harder agar) showed no rhlA-gfp reporter expression near the advancing edge. This difference in rhamnolipid gene expression can be explained by the necessity of quorum sensing for rhamnolipid production. We provide evidence that harder surfaces seem to limit induction of quorum sensing genes near the advancing swarm edge and these localized effects were sufficient to explain the lack of tendril formation on hard agar. We were unable to artificially stimulate rhamnolipid tendril formation with added acyl-homoserine lactone signals or increasing the carbon nutrients. This suggests that quorum sensing on surfaces is controlled in a manner that is not solely population dependent

    A systemic framework based on Soft OR approaches to support teamwork strategy: an aviation manufacturer Brazilian company case

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    The paper reports on the application of a combination of Operational Research (OR) approaches to a real-world case of re-designing the strategy of a department management team, in an aircraft manufacturing organization in Brazil. We combine approaches from ‘Soft’ OR Problem Structuring Methods in a multi-methodological framework arguing that this helps to discuss, develop and implement a new departmental strategy. The proposed framework uses elements of Soft Systems Methodology; Strategic Options Development and Analysis to understand and structure the situation; Value-Focused Thinking to define the means and objectives; and Value-Focused Brainstorming to highlight the potential solutions. We conceptualize a four-phased systemic framework linking elements of the above four ‘Soft’ OR approaches and apply it to a real-world case in a department where a new team leader was appointed with the specific brief to improve the departmental strategy and its performance in general. Findings suggest that combining the approaches into a framework encourages trust and participation from stakeholders which, in practice, is translated into an improved strategy for the organization. A reflection on the multi-methodological approach is proposed. Conclusions and points for further research are suggested

    Combined use of bacteriophage K and a novel bacteriophage to reduce Staphylococcus aureus biofilm formation

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    Biofilms are major causes of impairment of wound healing and patient morbidity. One of the most common and aggressive wound pathogens is Staphylococcus aureus, displaying a large repertoire of virulence factors and commonly reduced susceptibility to antibiotics, such as the spread of methicillin-resistant S. aureus (MRSA). Bacteriophages are obligate parasites of bacteria. They multiply intracellularly and lyse their bacterial host, releasing their progeny. We isolated a novel phage, DRA88, which has a broad host range among S. aureus bacteria. Morphologically, the phage belongs to the Myoviridae family and comprises a large double-stranded DNA (dsDNA) genome of 141,907 bp. DRA88 was mixed with phage K to produce a high-titer mixture that showed strong lytic activity against a wide range of S. aureus isolates, including representatives of the major international MRSA clones and coagulase-negative Staphylococcus. Its efficacy was assessed both in planktonic cultures and when treating established biofilms produced by three different biofilm-producing S. aureus isolates. A significant reduction of biofilm biomass over 48 h of treatment was recorded in all cases. The phage mixture may form the basis of an effective treatment for infections caused by S. aureus biofilms

    Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity

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    Anthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth's biodiversity. We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions. The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia. Declines peaked in the 1980s, and only 12% of declined species show signs of recovery, whereas 39% are experiencing ongoing decline. There is risk of further chytridiomycosis outbreaks in new areas. The chytridiomycosis panzootic represents the greatest recorded loss of biodiversity attributable to a disease

    Consumers’ values and behaviour in the Brazilian coffee-in-capsules market: Promoting circular economy

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    Coffee consumption is changing. Monodose, flavoured coffee capsules provide new experiences beyond the traditional custom of brewing coffee. While these pods mean access to a selection of premium coffee worldwide, they create huge quantities of plastic-aluminium packaging waste. This paper examines the novelty of coffee capsule consumption in Brazil in terms of consumers’ perspectives about ethical enterprise and environmental stewardship. We argue for ‘waste to resource’ management and applying reverse logistics to the coffee production supply chain. Based on Circular Economy principles and fuelled by the ‘green’ awareness of Brazilian coffee consumers themselves, we propose a conceptual framework to support business decision-making by adopting a systemic intervention from the consumer viewpoint. To structure and scope the problematic situation, we conducted over 40 interviews, using purposive sampling. Analytic Hierarchy Process (AHP), Value Focused Thinking (VFT) and Rich Picture Technique also informed our problem structuring approach. Findings illustrate that the ambition for a reverse supply chain in coffee capsule manufacturing presents real challenges to achieving circular practice. Yet, the eco-values of Brazilian coffee enthusiasts may be partly considered a ‘wealth of information flow’ and a potential driving force for change. This paper should be of interest to researchers and practitioners exploring how consumers may contribute to behavioural change, towards more circular business

    The ‘talk o’ the toon’?:An examination of the Heart of Midlothian and Hibernian football rivalry in Edinburgh, Scotland

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    Heart of Midlothian (Hearts) and Hibernian (Hibs) Football Clubs are historic football rivals based in Edinburgh, Scotland. Both clubs have past and present connections to sectarian identities resulting in their rivalry often being reductively labelled “a mini Old Firm” (a mini Rangers v Celtic rivalry). This reductionism misunderstands the genuine ethno-religious (sectarian) connections of both Edinburgh clubs and overlooks other significant factors that underpin and sustain the rivalry in 21st century Scotland. Hearts have British and military-related ‘remembrance’ signifiers and Hibs have Irish-Catholic signifiers and these do continue – under quite specific and sporadic conditions - to linger today. Yet both clubs also have additional aspects to their identities which underpin the rivalry and these relate to a failed take-over of Hibs by Hearts, to playing style, social class and geographical place. Utilising semi-structured and unstructured interviews and observation, we conclude that the Hearts-Hibs rivalry has entered a post-sectarian period where lingering sectarian signifiers sometimes reveal themselves - often when the two clubs play the Glasgow clubs Celtic and Rangers – but where more often, largely overlooked elements constitute the rivalry to a greater extent for large sections of both respective groups of supporters
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