Regulation of phenylacetic acid uptake is σ54 dependent in Pseudomonas putida CA-3

<p>Abstract</p> <p>Background</p> <p>Styrene is a toxic and potentially carcinogenic alkenylbenzene used extensively in the polymer processing industry. Significant quantities of contaminated liquid waste are generated annually as a consequence. However, styrene is not a true xenobiotic and microbial pathways for its aerobic assimilation, via an intermediate, phenylacetic acid, have been identified in a diverse range of environmental isolates. The potential for microbial bioremediation of styrene waste has received considerable research attention over the last number of years. As a result the structure, organisation and encoded function of the genes responsible for styrene and phenylacetic acid sensing, uptake and catabolism have been elucidated. However, a limited understanding persists in relation to host specific regulatory molecules which may impart additional control over these pathways. In this study the styrene degrader <it>Pseudomonas putida </it>CA-3 was subjected to random mini-Tn<it>5 </it>mutagenesis and mutants screened for altered styrene/phenylacetic acid utilisation profiles potentially linked to non-catabolon encoded regulatory influences.</p> <p>Results</p> <p>One mutant, D7, capable of growth on styrene, but not on phenylacetic acid, harboured a Tn<it>5 </it>insertion in the <it>rpoN </it>gene encoding σ54. Complementation of the D7 mutant with the wild type <it>rpoN </it>gene restored the ability of this strain to utilise phenylacetic acid as a sole carbon source. Subsequent RT-PCR analyses revealed that a phenylacetate permease, PaaL, was expressed in wild type <it>P. putida </it>CA-3 cells utilising styrene or phenylacetic acid, but could not be detected in the disrupted D7 mutant. Expression of plasmid borne <it>paaL </it>in mutant D7 was found to fully restore the phenylacetic acid utilisation capacity of the strain to wild type levels. Bioinformatic analysis of the <it>paaL </it>promoter from <it>P. putida </it>CA-3 revealed two σ⁵⁴consensus binding sites in a non-archetypal configuration, with the transcriptional start site being resolved by primer extension analysis. Comparative analyses of genomes encoding phenylacetyl CoA, (PACoA), catabolic operons identified a common association among styrene degradation linked PACoA catabolons in <it>Pseudomonas </it>species studied to date.</p> <p>Conclusions</p> <p>In summary, this is the first study to report RpoN dependent transcriptional activation of the PACoA catabolon <it>paaL </it>gene, encoding a transport protein essential for phenylacetic acid utilisation in <it>P. putida </it>CA-3. Bioinformatic analysis is provided to suggest this regulatory link may be common among styrene degrading <it>Pseudomonads</it>.</p

Ensayo de ladrillos a tracción

Not availableEn 1969 se comenzó en la Universidad de Salford un programa de investigación para el ensayo de elementos estructurales de fábrica de ladrillo, bajo los auspicios de la Brick Development Association. El trabajo iba dirigido a determinar la resistencia de los ladrillos bajo las tensiones a que ellos están sometidos en la práctica, que son predominantemente de tracción. Este artículo compara y contrasta los diferentes ensayos de tracción que se investigaron, mientras que un tercer miembro del equipo de investigación describe, en el artículo que continúa, la aplicación de las técnicas de fotoelasticidad a este trabajo

Modulation of plant autophagy during pathogen attack

In plants, the highly conserved catabolic process of autophagy has long been known as a means of maintaining cellular homeostasis and coping with abiotic stress conditions. Accumulating evidence has linked autophagy to immunity against invading pathogens, regulating plant cell death, and antimicrobial defences. In turn, it appears that phytopathogens have evolved ways not only to evade autophagic clearance but also to modulate and co-opt autophagy for their own benefit. In this review, we summarize and discuss the emerging discoveries concerning how pathogens modulate both host and self-autophagy machineries to colonize their host plants, delving into the arms race that determines the fate of interorganismal interaction.Fil: Leary, Alexandre Y. Imperial College London; Reino UnidoFil: Sanguankiattichai, Nattapong. University of Oxford; Reino UnidoFil: Duggan, Cian. Imperial College London; Reino UnidoFil: Tumtas, Yasin. Imperial College London; Reino UnidoFil: Pandey, Pooja. Imperial College London; Reino UnidoFil: Segretin, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Salguero Linares, Jose. Imperial College London; Reino UnidoFil: Savage, Zachary D. Imperial College London; Reino UnidoFil: Yow, Rui Jin. Imperial College London; Reino UnidoFil: Bozkurt, Tolga O.. Imperial College London; Reino Unid

Finite element analysis and comparison of human skulls using MRI driven 3D printing

This is the author accepted manuscript. The final version is available via the link in this recordPoster abstrac

SILICONE ARTHROPLASTY FOR TRAPEZIOMETACARPAL ARTHRITIS

Twenty-three patients who had undergone trapeziectomy and Helal silicone rubber ball interposition for trapeziometacarpal arthritis were reviewed. The average age at operation was 63 (range 48-84) years and the mean follow-up was 59 (range 12-138) months. Of the 23 patients reviewed, two had pain at rest and four had some discomfort on exertion. Mean post-operative thumb extension was 371 whilst mean palmar abduction was 401. Mean post-operative grip strength was 19 kg and thumb-pinch strength was 4.0 kg, 77% and 78% of the age-and sex-matched normal values. There were no cases of prosthetic dislocation, prosthetic fracture or silicone synovitis

New Tetrahedral Global Minimum for the 98-atom Lennard-Jones Cluster

A new atomic cluster structure corresponding to the global minimum of the 98-atom Lennard-Jones cluster has been found using a variant of the basin-hopping global optimization algorithm. The new structure has an unusual tetrahedral symmetry with an energy of -543.665361, which is 0.022404 lower than the previous putative global minimum. The new LJ_98 structure is of particular interest because its tetrahedral symmetry establishes it as one of only three types of exceptions to the general pattern of icosahedral structural motifs for optimal LJ microclusters. Similar to the other exceptions the global minimum is difficult to find because it is at the bottom of a narrow funnel which only becomes thermodynamically most stable at low temperature.Comment: 3 pages, 2 figures, revte

Low Myo‐inositol indicating astrocytic damage in a case series of neuromyelitis optica

Astrocytic necrosis is a prominent pathological feature of neuromyelitis optica (NMO) lesions and is clinically relevant. We report 5 NMO‐related cases, all with longitudinally extensive lesions in the upper cervical cord, who underwent cervical cord 1H‐magnetic resonance spectroscopy. Lower myo‐inositol/creatine values, suggesting astrocytic damage, were consistently found within the NMO lesions when compared with healthy controls and patients with multiple sclerosis (MS), who showed at least 1 demyelinating lesion at the same cord level. Therefore, the in vivo quantification of myo‐inositol may distinguish NMO from MS. This is an important step toward developing imaging markers for clinical trials in NMO

Test Plan to Assess Fire Effects on the Function of an Engineered Surface Barrier

Wildfire is a frequent perturbation in shrub steppe ecosystems, altering the flora, fauna, atmosphere, and soil of these systems. Research on the fire effects has focused mostly on natural ecosystems with essentially no attention on engineered systems like surface barriers. The scope of the project is to use a simulated wildfire to induce changes in an engineered surface barrier and document the effects on barrier performance. The main objective is to quantify the effects of burning and the resulting post-fire conditions on alterations in soil physical properties; hydrologic response, particularly the water balance; geochemical properties; and biological properties. A secondary objective is to use the lessons learned to maximize fire protection in the design of long-term monitoring systems based on electronic sensors. A simulated wildfire will be initiated, controlled and monitored at the 200-BP-1 barrier in collaboration with the Hanford Fire Department during the fall of 2008. The north half of the barrier will be divided into nine 12 x 12 m plots, each of which will be randomly assigned a fuel load of 2 kg m-2 or 4 kg m-2. Each plot will be ignited around the perimeter and flames allowed to carry to the centre. Any remaining unburned vegetation will be manually burned off using a drip torch. Progress of the fire and its effects will be monitored using point measurements of thermal, hydrologic, and biotic variables. Three measures of fire intensity will be used to characterize fire behavior: (1) flame height, (2) the maximum temperature at three vertical profile levels, and (3) total duration of elevated temperature at these levels. Pre-burn plant information, including species diversity, plant height, and canopy diameter will be measured on shrubs from the plots to be burned and from control plots at the McGee ranch. General assessments of shrub survival, recovery, and recruitment will be made after the fire. Near-surface soil samples will be collected pre- and post-burn to determine changes in the gravel content of the surface layer so as to quantify inflationary or deflationary responses to fire and to reveal the ability of the surface to resist post-fire erosive stresses. Measures of bulk density, water repellency, water retention, and hydraulic conductivity will be used to characterize changes in infiltration rates and water storage capacity following the fire. Samples will also be analyzed to quantify geochemical changes including changes in soil pH, cation exchange capacity, specific surface area, and the concentration of macro nutrients (e.g. N, P, K) and other elements such as Na, Mg, Ca, that are critical to the post-fire recovery revegetation. Soil CO2 emissions will be measured monthly for one year following the burn to document post-fire stimulation of carbon turnover and soil biogenic emissions. Surface and subsurface temperature measurements at and near monitoring installations will be used to document fire effects on electronic equipment. The results of this study will be used to bridge the gaps in knowledge on the effects of fire on engineered ecosystems (e.g. surface barriers), particularly the hydrologic and biotic characteristics that govern the water and energy balance. These results will also support the development of practical fire management techniques for barriers that are compatible with wildfire suppression strategies. Furthermore, lessons learned will be use to develop installation strategies needed to protect electronic monitoring equipment from the intense heat of fire and the potential damaging effects of smoke and fire extinguishing agents. Such information is needed to better understand long-term barrier performance under extreme conditions, especially if site maintenance and operational funding is lost for activities such as barrier revegetation

Meeting Report: GBIF hackathon-workshop on Darwin Core and sample data (22-24 May 2013)

The workshop-hackathon was convened by the Global Biodiversity Information Facility (GBIF) at its secretariat in Copenhagen over 22-24 May 2013 with additional support from several projects (RCN4GSC, EAGER, VertNet, BiSciCol, GGBN, and Micro B3). It assembled a team of experts to address the challenge of adapting the Darwin Core standard for a wide variety of sample data. Topics addressed in the workshop included 1) a review of outstanding issues in the Darwin Core standard, 2) issues relating to publishing of biodiversity data through Darwin Core Archives, 3) use of Darwin Core Archives for publishing sample and monitoring data, 4) the case for modifying the Darwin Core Text Guide specification to support many-to-many relations, and 5) the generalization of the Darwin Core Archive to a "Biodiversity Data Archive". A wide variety of use cases were assembled and discussed in order to inform further developments

Meeting Report: GBIF hackathon-workshop on Darwin Core and sample data (22-24 May 2013)

The workshop-hackathon was convened by the Global Biodiversity Information Facility (GBIF) at its secretariat in Copenhagen over 22-24 May 2013 with additional support from several projects (RCN4GSC, EAGER, VertNet, BiSciCol, GGBN, and Micro B3). It assembled a team of experts to address the challenge of adapting the Darwin Core standard for a wide variety of sample data. Topics addressed in the workshop included 1) a review of outstanding issues in the Darwin Core standard, 2) issues relating to publishing of biodiversity data through Darwin Core Archives, 3) use of Darwin Core Archives for publishing sample and monitoring data, 4) the case for modifying the Darwin Core Text Guide specification to support many-to-many relations, and 5) the generalization of the Darwin Core Archive to a "Biodiversity Data Archive". A wide variety of use cases were assembled and discussed in order to inform further developments