The crystal structure of Haloferax volcanii proliferating cell nuclear antigen reveals unique surface charge characteristics due to halophilic adaptation

Background: The high intracellular salt concentration re quired to maintain a halophilic lifestyle poses challenges to haloarchaeal proteins that must stay soluble, stable and functional in this extreme environment. Proliferating cell nuclear antigen (PCNA) is a fundamental protein involved in maintaining genome integrity, with roles in both DNA replication and repair. To investigate the halophilic adaptation of such a key protein we have crystallised and solved the structure of Haloferax volcanii PCNA (HvPCNA) to a resolution of 2.0 Å. Results: The overall architecture of HvPCNA is very similar to other known PCNAs, which are highly structurally conserved. Three commonly observed adaptations in halophilic proteins are higher surface acidity, bound ions and increased numbers of intermolecular ion pairs (in oligomeric proteins). HvPCNA possesses the former two adaptations but not the latter, despite functioning as a homotrimer. Strikingly, the positive surface charge considered key to PCNA's role as a sliding clamp is dramatically reduced in the halophilic protein. Instead, bound cations within the solvation shell of HvPCNA may permit sliding along negatively charged DNA by reducing electrostatic repulsion effects. Conclusion: The extent to which individual proteins adapt to halophilic conditions varies, presumably due to their diverse characteristics and roles within the cell. The number of ion pairs observed in the HvPCNA monomer-monomer interface wasunexpectedly low. This may reflect the fact that the trimer is intrinsically stable over a wide range of salt concentrations and therefore additional modifications for trimer maintenance in high salt conditions are not required. Halophilic proteins frequently bind anions and cations and in HvPCNA cation binding may compensate for the remarkable reduction in positive charge in the pore region, to facilitate functional interactions with DNA. In this way, HvPCNA may harness its environment as opposed to simply surviving in extreme halophilic conditions

Dynamic Application Integration Using Peer to Peer Technology

Today's business imperatives are clearer than ever. Businesses are trying to beat competitors by introducing new products to the market, deliver personalised services, increase customer loyalty and evolve at electronic speeds. These imperatives demand a technology infrastructure that is more flexible, more dynamic and more intelligent than ever. Java Web services based on Universal Description, Discovery and Integration (UDDI) are an evolution in e-business applications that will help businesses reach these goals and take Business-to-Business (B2B) to the next level. In the last couple of years, the concept of a Web Service (WS) has emerged as an important paradigm for general application integration in the internet environment. More particularly, WS is viewed as an important vehicle for the creation of dynamic e business applications and as a means for the Java 2 Enterprise Edition (J2EE) and Microsoft .NET platforms to come together. This will be achieved through WS standards and several companies have been collaborating in such standardisation activities. This Thesis describes research aiming to allow the dynamic integration of different software applications and information sources, including legacy systems, using the latest state of the art Internet technology called “Peer-to-Peer (P2P)”. The term “dynamic” is used in order to indicate that different software applications, in different geographical locations, that need to be integrated are able to establish a communication link and interchange data without manual intervention or without any intermediate integration server. To achieve this goal, several technologies have been combined, including Java Web Services and the Extensible Stylesheet Language (XML), in order to design, develop and implement an innovative architecture that will satisfy such requirements. Amongst others, the main programming language used is the widely accepted Java language, which acts catalytically in the creation of the system architecture described in this Thesis

Low-dose 2-Deoxy Glucose Stabilises Tolerogenic Dendritic Cells and Generates Potent in vivo Immunosuppressive Effects

Open Access via Springer Compact Agreement University of Aberdeen Development Trust Grant number RG14251, RG12663 Acknowledgements: We thank the University of Aberdeen Iain Fraser Flow Cytometry core facility, and the University of Aberdeen Histology and Microscopy core facility for processing of histology slides. The authors thank University of Aberdeen Medical Research Facility for technical assistance with in vivo experiments. We thank Dr. Tian Yu, Dr. Yi-Hsia Liu, Mrs Rosemary Fordyce, and Mrs Elizabeth Muckersie for technical assistance with in vivo and in vitro experiments. Funding: This work was supported by funds from the University of Aberdeen Development Trust Grants RG14251 and RG12663. Maria Christof was the recipient of a University of Aberdeen PhD Studentship. Samantha Le Sommer was funded by a Wellcome Trust ISSF Postdoctoral Fellowship.Peer reviewedPublisher PD

Reducing Intrathecal Baclofen Related Infections: Service Evaluation and Best Practice Guidelines

Objectives: Intrathecal baclofen (ITB) pumps are an effective treatment for spasticity; however infection rates have been reported in 3–26% of patients in the literature. The multidisciplinary ITB service has been established at The National Hospital for Neurology and Neurosurgery, UCLH, Queen Square, London for over 20 years. Our study was designed to clarify the rate of infection in our ITB patient cohort and secondly, to formulate and implement best practice guidelines and to determine prospectively, whether they effectively reduced infection rates. / Methods: Clinical record review of all patients receiving ITB pre‐intervention; January 2013–May 2015, and following practice changes; June 2016–June 2018. / Results: Four of 118 patients receiving ITB during the first time period (3.4%, annual incidence rate of infection 1.4%) developed an ITB‐related infection (three following ITB pump replacement surgery, one after initial implant). Infections were associated with 4.2% of ITB‐related surgical procedures. Three of four pumps required explantation. Following change in practice (pre‐operative chlorhexidine skin wash and intraoperative vancomycin wash of the fibrous pocket of the replacement site), only one of 160 ITB patients developed infection (pump not explanted) in the second time period (0.6%, annual incidence rate 0.3%). The infection rate related to ITB surgical procedures was 1.1%. In cases of ITB pump replacement, the infection rate was reduced to 3.3% from 17.6%. / Conclusions: This study suggests that a straightforward change in clinical practice may lower infection rates in patients undergoing ITB therapy

Domain wall fermions for planar physics

In 2+1 dimensions, Dirac fermions in reducible, i.e. four-component representations of the spinor algebra form the basis of many interesting model field theories and effective descriptions of condensed matter phenomena. This paper explores lattice formulations which preserve the global U(2N) symmetry present in the massless limit, and its breakdown to U(N)xU(N) implemented by three independent and parity-invariant fermion mass terms. I set out generalisations of the Ginsparg-Wilson relation, leading to a formulation of an overlap operator, and explore the remnants of the global symmetries which depart from the continuum form by terms of order of the lattice spacing. I also define a domain wall formulation in 2+1+1d, and present numerical evidence, in the form of bilinear condensate and meson correlator calculations in quenched non-compact QED using reformulations of all three mass terms, to show that U(2N) symmetry is recovered in the limit that the domain-wall separation L tends to infinity. The possibility that overlap and domain wall formulations of reducible fermions may coincide only in the continuum limit is discussed

Comparative antibacterial potential of selected aldehyde-based biocides and surfactants against planktonic Pseudomonas fluorescens

The antimicrobial efficacy of two aldehydebased biocides (glutaraldehyde, GTA, and orthophthalaldehyde, OPA) and two surfactants (cetyltrimethyl ammonium bromide, CTAB, and sodium dodecyl sulphate, SDS) was tested against planktonic Pseudomonas fluorescens. The antimicrobial effects were evaluated by respiratory activity as a measure of the oxygen uptake rate, adenosine triphosphate (ATP) release, outer membrane proteins (OMP) expression and cellular colour changes. The results were compared with the bacterial characteristics without chemical treatment. Tests in the presence of bovine serum albumin (BSA), in order to mimic a disinfection process in the real situation under dirty conditions, were performed according to the European Standard EN-1276. P. fluorescens was completely inactivated with OPA (minimum bactericidal concentration, MBC = 0.5 mM) and CTAB (MBC = 5 mM) and was resistant to GTA and SDS. Only CTAB promoted cellular disruption and consequent ATP release. The antimicrobial action of the chemicals tested was significantly reduced when BSA was introduced into the bacterial cultures, increasing markedly the MBC values. Additionally, the presence of BSA acted as a disruption protective agent when CTAB was applied and stimulated the bacterial respiratory activity when lower concentrations of SDS were tested. The OMP of the bacterial cells was affected by the application of both surfactants. OMP expression remained unaltered after biocide treatment. Bacterial colour change was noticed after treatment with biocides and surfactants. In summary, P. fluorescens was extremely resistant to GTA and SDS, with antimicrobial action being quenched markedly by the reaction with BSA.Instituto de Biotecnologia e Química Fina (IBQF).Fundação para a Ciência e a Tecnologia (FCT) - (Project CHEMBIO - POCI/BIO/61872/2004

Optimization for the Production of Surfactin with a New Synergistic Antifungal Activity

-surfactin and the optimization of its production by the response surface method.O. A production of 134.2 mg/L, which were in agreement with the prediction, was observed in a verification experiment. In comparison to the production of original level (88.6 mg/L), a 1.52-fold increase had been obtained.-surfactin