Alternative outlets for sustaining photosynthetic electron transport during dark-to-light transitions.

Environmental stresses dramatically impact the balance between the production of photosynthetically derived energetic electrons and Calvin-Benson-Bassham cycle (CBBC) activity; an imbalance promotes accumulation of reactive oxygen species and causes cell damage. Hence, photosynthetic organisms have developed several strategies to route electrons toward alternative outlets that allow for storage or harmless dissipation of their energy. In this work, we explore the activities of three essential outlets associated with Chlamydomonas reinhardtii photosynthetic electron transport: (i) reduction of O2 to H2O through flavodiiron proteins (FLVs) and (ii) plastid terminal oxidases (PTOX) and (iii) the synthesis of starch. Real-time measurements of O2 exchange have demonstrated that FLVs immediately engage during dark-to-light transitions, allowing electron transport when the CBBC is not fully activated. Under these conditions, we quantified maximal FLV activity and its overall capacity to direct photosynthetic electrons toward O2 reduction. However, when starch synthesis is compromised, a greater proportion of the electrons is directed toward O2 reduction through both the FLVs and PTOX, suggesting an important role for starch synthesis in priming/regulating CBBC and electron transport. Moreover, partitioning energized electrons between sustainable (starch; energetic electrons are recaptured) and nonsustainable (H2O; energetic electrons are not recaptured) outlets is part of the energy management strategy of photosynthetic organisms that allows them to cope with the fluctuating conditions encountered in nature. Finally, unmasking the repertoire and control of such energetic reactions offers new directions for rational redesign and optimization of photosynthesis to satisfy global demands for food and other resources

Categorization of compensatory motions in transradial myoelectric prosthesis users

Background: Prosthesis users perform various compensatory motions to accommodate for the loss of the hand and wrist as well as the reduced functionality of a prosthetic hand. Objectives: Investigate different compensation strategies that are performed by prosthesis users. Study Design: Comparative analysis Methods: 20 able-bodied subjects and 4 prosthesis users performed a set of bimanual activities. Movements of the trunk and head were recorded using a motion capture system, and a digital video recorder. Clinical motion angles were calculated to assess the compensatory motions made by the prosthesis users. The video recording also assisted in visually identifying the compensations. Results: Compensatory motions by the prosthesis users were evident in the tasks performed (slicing and stirring activities) as compared to the benchmark of able-bodied subjects. Compensations took the form of a measured increase in range of motion, an observed adoption of a new posture during task execution, and pre-positioning of items in the workspace prior to initiating a given task. Conclusion: Compensatory motions were performed by prosthesis users during the selected tasks. These can be categorized into three different types of compensations

Determination of total and available fractions of PAHs by SPME in oily wastewaters : overcoming interference from NAPL and NOM

Background, aim, and scope Polycyclic aromatic hydrocarbons (PAHs) are often found in oily wastewaters. Their presence is usually the result of human activities and has a negative effect on the environment. One important step in addressing this problem is to evaluate the effectiveness of PAH removal by biological processes since these are the most cost-effective treatments known today. Many techniques are presently available for PAH determination in wastewaters. Solid phase microextracion (SPME) is known to be one of the most effective techniques for this purpose. When analyzing complex matrices with substances such as natural organic matter (NOM) and non-aqueous phase liquids (NAPL), it is important to differentiate the free dissolved PAH from matrix-bonded PAH. PAHs associated with the bonded fraction are less susceptible to biological treatment. The present study concerns the development of a simple and suitable methodology for the determination of the freely dissolved and the total fraction of PAHs present in oily wastewaters. The methodology was then applied to an oily wastewater from a fuel station retention basin. Material and methods Headspace SPME was used for analyzing PAH since the presence of a complex or dirty matrix in direct contact with the fiber may damage it. Four model PAHs—anthracene, fluorene, phenanthrene, and pyrene—were analyzed by GC-MS. Negligible depletion SPME technique was used to determine the free fraction. Total PAH was determined by enhancing the mass transfer from the bonded phase to the freely dissolved phase by temperature optimization and the use of the method of standard additions. The PAH absorption kinetics were determined in order to define the optimal sampling conditions for this method. The fitting of the experimental data to a mathematical model was accomplished using Berkeley Madonna software. Humic acid and silicon oil were used as model NOM and NAPL, respectively, to study the effect of these compounds on the decrease of SPME response. Then, the method was evaluated with wastewater from a fuel station spill retention basin. Results The SPME kinetic parameters—k 1 (uptake rate), k 2 (desorption rate), and K SPME (partition coefficient)—were determined from experimental data modeling. The determination of the free fraction required 15-min sampling to ensure that PAH depletion from sample was below 1%. For total PAH, a 30-min extraction at 100°C ensured the maximum signal response in the GC-MS. For the determination of free and total PAHs, extractions were performed before reaching the SPME equilibrium. The wastewater used in this study had no free fraction of the analyzed PAHs. However, the four studied PAHs were found when the method for total PAH was used. Discussion The addition of NOM and NAPL dramatically decreased the efficiency of the SPME. This decrease was the result of a greater partition of the PAHs to the NAPL and NOM phases. This fact was also observed in the analysis of the fuel station spill retention basin, where no free PAH was measured. However, using the method of standard addition for the determination of total PAH, it was possible to quantify all four PAHs. Conclusions The method developed in the present study was found to be adequate to differentiate between free and total PAH present in oily wastewater. It was determined that the presence of NOM and NAPL had a negative effect on SPME efficiency. Recommendations and perspectives The presence of binding substances had a great influence on SPME kinetics. Therefore, it is of extreme importance to determine their degree of interference when analyzing oily wastewaters or results can otherwise be erroneous. Other factors influencing the total PAH determinations should be considered in further studies.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/ 18816/2004, POCI/AMB/61044/200

Characterizing genomic alterations in cancer by complementary functional associations.

Systematic efforts to sequence the cancer genome have identified large numbers of mutations and copy number alterations in human cancers. However, elucidating the functional consequences of these variants, and their interactions to drive or maintain oncogenic states, remains a challenge in cancer research. We developed REVEALER, a computational method that identifies combinations of mutually exclusive genomic alterations correlated with functional phenotypes, such as the activation or gene dependency of oncogenic pathways or sensitivity to a drug treatment. We used REVEALER to uncover complementary genomic alterations associated with the transcriptional activation of β-catenin and NRF2, MEK-inhibitor sensitivity, and KRAS dependency. REVEALER successfully identified both known and new associations, demonstrating the power of combining functional profiles with extensive characterization of genomic alterations in cancer genomes

Complement-Mediated Virus Infectivity Neutralisation by HLA Antibodies Is Associated with Sterilising Immunity to SIV Challenge in the Macaque Model for HIV/AIDS.

Sterilising immunity is a desired outcome for vaccination against human immunodeficiency virus (HIV) and has been observed in the macaque model using inactivated simian immunodeficiency virus (SIV). This protection was attributed to antibodies specific for cell proteins including human leucocyte antigens (HLA) class I and II incorporated into virions during vaccine and challenge virus preparation. We show here, using HLA bead arrays, that vaccinated macaques protected from virus challenge had higher serum antibody reactivity compared with non-protected animals. Moreover, reactivity was shown to be directed against HLA framework determinants. Previous studies failed to correlate serum antibody mediated virus neutralisation with protection and were confounded by cytotoxic effects. Using a virus entry assay based on TZM-bl cells we now report that, in the presence of complement, serum antibody titres that neutralise virus infectivity were higher in protected animals. We propose that complement-augmented virus neutralisation is a key factor in inducing sterilising immunity and may be difficult to achieve with HIV/SIV Env-based vaccines. Understanding how to overcome the apparent block of inactivated SIV vaccines to elicit anti-envelope protein antibodies that effectively engage the complement system could enable novel anti-HIV antibody vaccines that induce potent, virolytic serological response to be developed

MultiSig: a new high-precision approach to the analysis of complex biomolecular systems

MultiSig is a newly developed mode of analysis of sedimentation equilibrium (SE) experiments in the analytical ultracentrifuge, having the capability of taking advantage of the remarkable precision (~0.1 % of signal) of the principal optical (fringe) system employed, thus supplanting existing methods of analysis through reducing the ‘noise’ level of certain important parameter estimates by up to orders of magnitude. Long-known limitations of the SE method, arising from lack of knowledge of the true fringe number in fringe optics and from the use of unstable numerical algorithms such as numerical differentiation, have been transcended. An approach to data analysis, akin to ‘spatial filtering’, has been developed, and shown by both simulation and practical application to be a powerful aid to the precision with which near-monodisperse systems can be analysed, potentially yielding information on protein-solvent interaction. For oligo- and poly-disperse systems the information returned includes precise average mass distributions over both cell radial and concentration ranges and mass-frequency histograms at fixed radial positions. The application of MultiSig analysis to various complex heterogenous systems and potentially multiply-interacting carbohydrate oligomers is described

Urinary Extracellular Domain of Neurotrophin Receptor p75 as a Biomarker for Amyotrophic Lateral Sclerosis in a Chinese cohort

To comprehensively assess whether p75ECD in urine could be a candidate biomarker for ALS evaluation. Urine samples were collected from 101 ALS patients, 108 patients with other neurological disease (OND) and 97 healthy controls. 61 ALS patients were followed up with clinical data including ALSFRS-r every 6 to 12 months, 23 ALS patients died and 17 ALS patients lost touch during follow up period. Enzyme-linked immunoassay was employed to determine urine p75ECD concentration. The ALSFRS-r was employed to assess the severity of ALS. The concentration of p75ECD in ALS was significantly higher than that of OND and CTRL (p < 0.001). Additionally, urine p75ECD concentrations in ALS-definite grade patients were significantly higher than that in ALS-probable grade and ALS-possible grade patients (p < 0.001). Higher urine p75ECD concentrations were correlated with increased clinical stage (p = 0.0309); urine p75ECD concentrations and ALSFRS-r were negatively correlated (p = 0.022); and urine p75ECD concentration in the fast-progressing ALS group was significantly higher than that in slow-progression (p = 0.0026). Our finding indicates that urine p75ECD concentration provides additional evidence for patients with clinically suspected ALS, and can be employed to evaluate ALS-severity

Conclusions on motor control depend on the type of model used to represent the periphery

Within the field of motor control, there is no consensus on which kinematic and kinetic aspects of movements are planned or controlled. Perturbing goal-directed movements is a frequently used tool to answer this question. To be able to draw conclusions about motor control from kinematic responses to perturbations, a model of the periphery (i.e., the skeleton, muscle-tendon complexes, and spinal reflex circuitry) is required. The purpose of the present study was to determine to what extent such conclusions depend on the level of simplification with which the dynamical properties of the periphery are modeled. For this purpose, we simulated fast goal-directed single-joint movement with four existing types of models. We tested how three types of perturbations affected movement trajectory if motor commands remained unchanged. We found that the four types of models of the periphery showed different robustness to the perturbations, leading to different predictions on how accurate motor commands need to be, i.e., how accurate the knowledge of external conditions needs to be. This means that when interpreting kinematic responses obtained in perturbation experiments the level of error correction attributed to adaptation of motor commands depends on the type of model used to describe the periphery

The conserved C-terminus of the PcrA/UvrD helicase interacts directly with RNA polymerase

Copyright: © 2013 Gwynn et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a Wellcome Trust project grant to MD (Reference: 077368), an ERC starting grant to MD (Acronym: SM-DNA-REPAIR) and a BBSRC project grant to PM, NS and MD (Reference: BB/I003142/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Mice lacking endoglin in macrophages show an impaired immune response

24 p.-9 fig.-1 tab. Ojeda Fernández, Luisa et al.Endoglin is an auxiliary receptor for members of the TGF-β superfamily and plays an important role in the homeostasis of the vessel wall. Mutations in endoglin gene (ENG) or in the closely related TGF-β receptor type I ACVRL1/ALK1 are responsible for a rare dominant vascular dysplasia, the Hereditary Hemorrhagic Telangiectasia (HHT), or Rendu-OslerWeber syndrome. Endoglin is also expressed in human macrophages, but its role in macrophage function remains unknown. In this work, we show that endoglin expression is triggered during the monocyte-macrophage differentiation process, both in vitro and during the in vivo differentiation of blood monocytes recruited to foci of inflammation in wild-type C57BL/6 mice. To analyze the role of endoglin in macrophages in vivo, an endoglin myeloid lineage specific knock-out mouse line (Engfl/flLysMCre) was generated. These mice show a predisposition to develop spontaneous infections by opportunistic bacteria. Engfl/flLysMCre mice also display increased survival following LPS-induced peritonitis, suggesting a delayed immune response. Phagocytic activity is impaired in peritoneal macrophages, altering one of the main functions of macrophages which contributes to the initiation of the immune response. We also observed altered expression of TGF-β1 target genes in endoglin deficient peritoneal macrophages. Overall, the altered immune activity of endoglin deficient macrophages could help to explain the higher rate of infectious diseases seen in HHT1 patients.This work was funded by: Ministerio de Economía y Competitividad of Spain (SAF2011-23475 to LMB; SAF2013-43421-R and SAF2010- 19222 to CB.Peer reviewe