1,857 research outputs found
Sequencing of IncX-plasmids suggests ubiquity of mobile forms of a biofilm-promoting gene cassette recruited from <em>Klebsiella pneumoniae</em>
Plasmids are a highly effective means with which genetic traits that influence human health, such as virulence and antibiotic resistance, are disseminated through bacterial populations. The IncX-family is a hitherto sparsely populated group of plasmids that are able to thrive within Enterobacteriaceae. In this study, a replicon-centric screening method was used to locate strains from wastewater sludge containing plasmids belonging to the IncX-family. A transposon aided plasmid capture method was then employed to transport IncX-plasmids from their original hosts (and co-hosted plasmids) into a laboratory strain (Escherichia coli Genehogs®) for further study. The nucleotide sequences of the three newly isolated IncX-plasmids (pLN126_33, pMO17_54, pMO440_54) and the hitherto un-sequenced type-plasmid R485 revealed a remarkable occurrence of whole or partial gene cassettes that promote biofilm-formation in Klebsiella pneumonia or E. coli, in all four instances. Two of the plasmids (R485 and pLN126_33) were shown to directly induce biofilm formation in a crystal violet retention assay in E. coli. Sequence comparison revealed that all plasmid-borne forms of the type 3 fimbriae encoding gene cassette mrkABCDF were variations of a composite transposon Tn6011 first described in the E. coli IncX plasmid pOLA52. In conclusion, IncX-plasmids isolated from Enterobacteriaceae over almost 40 years and on three different continents have all been shown to carry a type 3 fimbriae gene cassette mrkABCDF stemming from pathogenic K. pneumoniae. Apart from contributing general knowledge about IncX-plasmids, this study also suggests an apparent ubiquity of a mobile form of an important virulence factor and is an illuminating example of the recruitment, evolution and dissemination of genetic traits through plasmid-mediated horizontal gene transfer
Genome sequence of Pseudomonas aeruginosa strain DK1-NH57388A, a stable mucoid cystic fibrosis isolate
Pseudomonas aeruginosa is an important opportunistic pathogen associated with chronic pulmonary infections and mortality in cystic fibrosis (CF) patients. Here, we present the complete genome sequence of stable mucoid P. aeruginosa strain DK1-NH57388A, a CF isolate which has previously been used to establish chronic lung infections in an animal model
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Post-Brexit no-trade-deal scenario: Short-term consumer benefit at the expense of long-term economic development
After the United Kingdom has left the European Union it remains unclear whether the two parties can successfully negotiate and sign a trade agreement within the transition period. Ongoing negotiations, practical obstacles and resulting uncertainties make it highly unlikely that economic actors would be fully prepared to a “no-trade-deal” situation. Here we provide an economic shock simulation of the immediate aftermath of such a post-Brexit no-trade-deal scenario by computing the time evolution of more than 1.8 million interactions between more than 6,600 economic actors in the global trade network. We find an abrupt decline in the number of goods produced in the UK and the EU. This sudden output reduction is caused by drops in demand as customers on the respective other side of the Channel incorporate the new trade restriction into their decision-making. As a response, producers reduce prices in order to stimulate demand elsewhere. In the short term consumers benefit from lower prices but production value decreases with potentially severe socio-economic consequences in the longer term
Future heat stress to reduce people’s purchasing power
With increasing carbon emissions rising temperatures are likely to impact our economies and societies profoundly. In particular, it has been shown that heat stress can strongly reduce labor productivity. The resulting economic perturbations can propagate along the global supply network. Here we show, using numerical simulations, that output losses due to heat stress alone are expected to increase by about 24% within the next 20 years, if no additional adaptation measures are taken. The subsequent market response with rising prices and supply shortages strongly reduces the consumers’ purchasing power in almost all countries including the US and Europe with particularly strong effects in India, Brazil, and Indonesia. As a consequence, the producing sectors in many regions temporarily benefit from higher selling prices while decreasing their production in quantity, whereas other countries suffer losses within their entire national economy. Our results stress that, even though climate shocks may stimulate economic activity in some regions and some sectors, their unpredictability exerts increasing pressure on people’s livelihood
No Free Lunch for Avoiding Clustering Vulnerabilities in Distributed Systems
Emergent design failures are ubiquitous in complex systems, and often arise
when system elements cluster. Approaches to systematically reduce clustering
could improve a design's resilience, but reducing clustering is difficult if it
is driven by collective interactions among design elements. Here, we use
techniques from statistical physics to identify mechanisms by which spatial
clusters of design elements emerge in complex systems modelled by heterogeneous
networks. We find that, in addition to naive, attraction-driven clustering,
heterogeneous networks can exhibit emergent, repulsion-driven clustering. We
draw quantitative connections between our results on a model system in naval
engineering to entropy-driven phenomena in nanoscale self-assembly, and give a
general argument that the clustering phenomena we observe should arise in many
distributed systems. We identify circumstances under which generic design
problems will exhibit trade-offs between clustering and uncertainty in design
objectives, and we present a framework to identify and quantify trade-offs to
manage clustering vulnerabilities.Comment: 20 pages, 5 figure
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