Phase Transition Induced Fission in Lipid Vesicles

In this work we demonstrate how the first order phase transition in giant unilamellar vesicles (GUVs) can function as a trigger for membrane fission. When driven through their gel-fluid phase transition GUVs exhibit budding or pearl formation. These buds remain connected to the mother vesicle presumably by a small neck. Cooling these vesicles from the fluid phase (T>Tm) through the phase transition into the gel state (T<Tm), leads to complete rupture and fission of the neck, while the mother vesicle remains intact. Pearling tubes which formed upon heating break-up and decay into multiple individual vesicles which then diffuse freely. Finally we demonstrate that mimicking the intracellular bulk viscosity by increasing the bulk viscosity to 40cP does not affect the overall fission process, but leads to a significant decrease in size of the released vesicles

Handling strategies for termites in the Azores

As térmitas estão perfeitamente estabelecidas nos Açores e constituem já uma praga de dimensões apreciadas nas zonas urbanas. Com base no conhecimento actual, é impossível erradicar as térmitas dos Açores. São conhecidas, actualmente, três espécies de térmitas nos Açores: uma térmita de madeira seca, a Cryptotermes brevis, uma térmita de madeira viva, a Kalotermes flavicollis, e uma térmita subterrânea, a Reticulitermes grassei. Qualquer que seja a estratégia de infestação, todas estas espécies irão causar grandes prejuízos económicos aos açorianos, nas próximas décadas, sendo as formas de combate e gestão diferentes para as três espécies. Com base na investigação científica realizada no último ano, em relação à espécie de térmita de madeira seca, Cryptotermes brevis, torna-se claro que as principais estratégias de gestão passam por: 1) evitar a dispersão das espécies entre ilhas; 2) melhorar as medidas de quarentena para, assim, evitar a entrada de novas espécies no arquipélago; 3) melhorar as técnicas de inspecção e treinar novos inspectores; 4) educar as pessoas para lidarem com a gestão dos insectos alados; 5) tratar o mobiliário com uma série de técnicas recentemente disponibilizadas (Bolhas de gás com CO2 ou N2) ou através do simples uso do frio, bem como do calor do sol; 6) remover as peças de madeira muito infestadas e proceder à sua substituição por peças de metal ou madeira pré-tratada com químicos em autoclave; 7) usar químicos em tratamentos localizados, apenas, quando a infestação tiver um carácter de fraca ou média infestação e ter sempre o cuidado de seleccionar o químico considerado mais adequado com base nos dados experimentais; 8) testar a possibilidade de utilizar medidas de controlo em grande escala, com base no uso de fumigação por gases ou por calor; 9) criar nova legislação.ABSTRACT: Termites are well-established and are serious pest of structural wood in the Azores. Eradication of termites cannot currently be achieved. Three species of termites are currently known from the archipelago (dry-wood termite Cryptotermes brevis, living trees Kalotermes flavicollis and subterranean termite Reticulitermes grassei). Whatever the infestation strategy, all these three species will cause enormous economic impact in the next decades in the Azores, and the types of control that are needed are entirely different for the three. As a result of the scientific research performed with the dry-wood termite Cryptotermes brevis in the last year it is now clear that the main management strategies are: 1) to avoid further dispersal between islands; 2) to improve quarantine measures in order to avoid the entrance in the archipelago of new termite species; 3) to improve inspection techniques and train new inspectors; 4) to educate home-owners to manage alates spread; 5) to treat furniture with newly available techniques (e.g., Gas Bubble with non-toxic physical controls such as CO2, or N2 gas) or simple use of "sun heat" or extreme cold; 6) to remove all highly infested wood and replace it with new materials such as metal parts or pressure-treated wood when (re)building; 7) to use chemicals in spot-treatments only when the infestation is moderate to small and selecting the most adequate chemical based on experimental grounds; 8) to test the possibility of using in the Azores whole-block control usually by gas or heat fumigation; 9) to create new legislation

Probing a Complex of Cytochromecand Cardiolipin by Magnetic Circular Dichroism Spectroscopy: Implications for the Initial Events in Apoptosis

Oxidation of cardiolipin (CL) by its complex with cytochrome c (cyt c) plays a crucial role in triggering apoptosis. Through a combination of magnetic circular dichroism spectroscopy and potentiometric titrations, we show that both the ferric and ferrous forms of the heme group of a CL:cyt c complex exist as multiple conformers at a physiologically relevant pH of 7.4. For the ferric state, these conformers are His/Lys- and His/OH–-ligated. The ferrous state is predominantly high-spin and, most likely, His/–. Interconversion of the ferric and ferrous conformers is described by a single midpoint potential of -80 ± 9 mV vs SHE. These results suggest that CL oxidation in mitochondria could occur by the reaction of molecular oxygen with the ferrous CL:cyt c complex in addition to the well-described reaction of peroxides with the ferric form

Incidence of community-acquired lower respiratory tract infections and pneumonia among older adults in the United Kingdom: a population-based study.

Community-acquired lower respiratory tract infections (LRTI) and pneumonia (CAP) are common causes of morbidity and mortality among those aged ≥65 years; a growing population in many countries. Detailed incidence estimates for these infections among older adults in the United Kingdom (UK) are lacking. We used electronic general practice records from the Clinical Practice Research Data link, linked to Hospital Episode Statistics inpatient data, to estimate incidence of community-acquired LRTI and CAP among UK older adults between April 1997-March 2011, by age, sex, region and deprivation quintile. Levels of antibiotic prescribing were also assessed. LRTI incidence increased with fluctuations over time, was higher in men than women aged ≥70 and increased with age from 92.21 episodes/1000 person-years (65-69 years) to 187.91/1000 (85-89 years). CAP incidence increased more markedly with age, from 2.81 to 21.81 episodes/1000 person-years respectively, and was higher among men. For both infection groups, increases over time were attenuated after age-standardisation, indicating that these rises were largely due to population aging. Rates among those in the most deprived quintile were around 70% higher than the least deprived and were generally higher in the North of England. GP antibiotic prescribing rates were high for LRTI but lower for CAP (mostly due to immediate hospitalisation). This is the first study to provide long-term detailed incidence estimates of community-acquired LRTI and CAP in UK older individuals, taking person-time at risk into account. The summary incidence commonly presented for the ≥65 age group considerably underestimates LRTI/CAP rates, particularly among older individuals within this group. Our methodology and findings are likely to be highly relevant to health planners and researchers in other countries with aging populations

Analysis of Heme Iron Coordination in DGCR8: The Heme-Binding Component of the Microprocessor Complex

DGCR8 is the RNA-binding partner of the nuclease Drosha. Their complex (the “Microprocessor”) is essential for processing of long, primary microRNAs (pri-miRNAs) in the nucleus. Binding of heme to DGCR8 is essential for pri-miRNA processing. On the basis of the split Soret ultraviolet–visible (UV–vis) spectrum of ferric DGCR8, bis-thiolate sulfur (cysteinate, Cys–) heme iron coordination of DGCR8 heme iron was proposed. We have characterized DGCR8 heme ligation using the Δ276 DGCR8 variant and combined electron paramagnetic resonance (EPR), magnetic circular dichroism (MCD), electron nuclear double resonance, resonance Raman, and electronic absorption spectroscopy. These studies indicate DGCR8 bis-Cys heme iron ligation, with conversion from bis-thiolate (Cys–/Cys–) axial coordination in ferric DGCR8 to bis-thiol (CysH/CysH) coordination in ferrous DGCR8. Pri-miRNA binding does not perturb ferric DGCR8’s optical spectrum, consistent with the axial ligand environment being separated from the substrate-binding site. UV–vis absorption spectra of the FeII and FeII–CO forms indicate discrete species exhibiting peaks with absorption coefficients substantially larger than those for ferric DGCR8 and that previously reported for a ferrous form of DGCR8. Electron–nuclear double resonance spectroscopy data exclude histidine or water as axial ligands for ferric DGCR8 and favor bis-thiolate coordination in this form. UV–vis MCD and near-infrared MCD provide data consistent with this conclusion. UV–vis MCD data for ferrous DGCR8 reveal features consistent with bis-thiol heme iron coordination, and resonance Raman data for the ferrous–CO form are consistent with a thiol ligand trans to the CO. These studies support retention of DGCR8 cysteine coordination upon reduction, a conclusion distinct from those of previous studies of a different ferrous DGCR8 isoform

Phenotypic redshifts with self-organizing maps: A novel method to characterize redshift distributions of source galaxies for weak lensing

Wide-field imaging surveys such as the Dark Energy Survey (DES) rely on coarse measurements of spectral energy distributions in a few filters to estimate the redshift distribution of source galaxies. In this regime, sample variance, shot noise, and selection effects limit the attainable accuracy of redshift calibration and thus of cosmological constraints. We present a new method to combine wide-field, few-filter measurements with catalogs from deep fields with additional filters and sufficiently low photometric noise to break degeneracies in photometric redshifts. The multi-band deep field is used as an intermediary between wide-field observations and accurate redshifts, greatly reducing sample variance, shot noise, and selection effects. Our implementation of the method uses self-organizing maps to group galaxies into phenotypes based on their observed fluxes, and is tested using a mock DES catalog created from N-body simulations. It yields a typical uncertainty on the mean redshift in each of five tomographic bins for an idealized simulation of the DES Year 3 weak-lensing tomographic analysis of $\sigma_{\Delta z} = 0.007$, which is a 60% improvement compared to the Year 1 analysis. Although the implementation of the method is tailored to DES, its formalism can be applied to other large photometric surveys with a similar observing strategy.Comment: 24 pages, 11 figures; matches version accepted to MNRA

Acquisition of pneumococci specific effector and regulatory Cd4+ T cells localising within human upper respiratory-tract mucosal lymphoid tissue

The upper respiratory tract mucosa is the location for commensal Streptococcus (S.) pneumoniae colonization and therefore represents a major site of contact between host and bacteria. The CD4(+) T cell response to pneumococcus is increasingly recognised as an important mediator of immunity that protects against invasive disease, with data suggesting a critical role for Th17 cells in mucosal clearance. By assessing CD4 T cell proliferative responses we demonstrate age-related sequestration of Th1 and Th17 CD4(+) T cells reactive to pneumococcal protein antigens within mucosal lymphoid tissue. CD25(hi) T cell depletion and utilisation of pneumococcal specific MHCII tetramers revealed the presence of antigen specific Tregs that utilised CTLA-4 and PDL-1 surface molecules to suppress these responses. The balance between mucosal effector and regulatory CD4(+) T cell immunity is likely to be critical to pneumococcal commensalism and the prevention of unwanted pathology associated with carriage. However, if dysregulated, such responses may render the host more susceptible to invasive pneumococcal infection and adversely affect the successful implementation of both polysaccharide-conjugate and novel protein-based pneumococcal vaccines

Pre-Admission Statin Use and In-Hospital Severity of 2009 Pandemic Influenza A(H1N1) Disease

In this group of patients hospitalized with pandemic influenza, a significant beneficial effect of pre-admission statin use on the in-hospital course of illness was not identified. Although the database from which these observations are derived represents the largest available suitable UK hospital cohort, a larger study would be needed to confirm whether there is any benefit in this setting