A meta‐analysis on growth,physiological, and biochemical responses of woody species to ground‐level ozone highlights the role of plant functional types

The carbon‐sink strength of temperate and boreal forests at midlatitudes of the northern hemisphere is decreased by ozone pollution, but knowledge on subtropical evergreen broadleaved forests is missing. Taking the dataset from Chinese studies covering temperate and subtropical regions, effects of elevated ozone concentration ([O₃]) on growth, biomass, and functional leaf traits of different types of woody plants were quantitatively evaluated by meta‐analysis. Elevated mean [O₃] of 116 ppb reduced total biomass of woody plants by 14% compared with control (mean [O₃] of 21 ppb). Temperate species from China were more sensitive to O₃ than those from Europe and North America in terms of photosynthesis and transpiration. Significant reductions in chlorophyll content, chlorophyll fluorescence parameters, and ascorbate peroxidase induced significant injury to photosynthesis and growth (height and diameter). Importantly, subtropical species were significantly less sensitive to O₃ than temperate ones, whereas deciduous broadleaf species were significantly more sensitive than evergreen broadleaf and needle‐leaf species. These findings suggest that carbon‐sink strength of Chinese forests is reduced by present and future [O₃] relative to control (20–40 ppb). Given that (sub)‐tropical evergreen broadleaved species dominate in Chinese forests, estimation of the global carbon‐sink constraints due to [O₃] should be re‐evaluated.     

Up-regulation of the Kv3.4 potassium channel subunit in early stages of Alzheimer's disease

Gene expression throughout the different stages of Alzheimer's disease was analysed in samples from cerebral cortex. The gene encoding the voltage-gated potassium channel Kv3.4 was already overexpressed in early stages of the disease, and in advanced stages Kv3.4 was present at high levels in neurodegenerative structures. This subunit regulates delayed-rectifier currents, which are primary determinants of spike repolarization in neurones. In unique samples from a patient with Alzheimer's disease whose amount of amyloid plaques was decreased by beta amyloid immunization, Kv3.4 was overexpressed. The channel subunit was expressed in the neuropil, in the remaining conventional plaques in the frontal cortex and in collapsed plaques in the orbitary cortex. Therefore, amyloid deposition in plaques does not seem to be responsible for the increase in Kv3.4 levels. Nevertheless, Kv3.4 up-regulation is related to amyloid pathology, given that transgenic mice with the Swedish mutation of amyloid precursor protein showed increased expression of Kv3.4. Up-regulation of voltage-gated potassium channel subunits alters potassium currents in neurones and leads to altered synaptic activity that may underlie the neurodegeneration observed in Alzheimer's disease. Thus, Kv3.4 likely represents a novel therapeutic target for the disease.     

The nuclear cofactor DOR regulates autophagy in mammalian and Drosophila cells

The regulation of autophagy in metazoans is only partly understood, and there is a need to identify the proteins that control this process. The diabetes‐ and obesity‐regulated gene (DOR), a recently reported nuclear cofactor of thyroid hormone receptors, is expressed abundantly in metabolically active tissues such as muscle. Here, we show that DOR shuttles between the nucleus and the cytoplasm, depending on cellular stress conditions, and re‐localizes to autophagosomes on autophagy activation. We demonstrate that DOR interacts physically with autophagic proteins Golgi‐associated ATPase enhancer of 16 kDa (GATE16) and microtubule‐associated protein 1A/1B‐light chain 3. Gain‐of‐function and loss‐of‐function studies indicate that DOR stimulates autophagosome formation and accelerates the degradation of stable proteins. CG11347, the DOR Drosophila homologue, has been predicted to interact with the Drosophila Atg8 homologues, which suggests functional conservation in autophagy. Flies lacking CG11347 show reduced autophagy in the fat body during pupal development. All together, our data indicate that DOR regulates autophagosome formation and protein degradation in mammalian and Drosophila cells.     

Ozone in Spain's national parks and protected forests

In general, it is difficult to measure air pollutant concentrations in remote areas, as they are mostly national parks and protected areas. Passive samplers provide an accurate and inexpensive method for measuring cumulative exposures of different air pollutants. They have been used to collect ozone data in both laboratory and field at different geographical scales. The objective of the present study is to fill the knowledge gap regarding air quality in remote areas of Spain, such as national parks and protected areas. Because there were no systematic data sets on the main air pollutants that could affect these areas, an air quality measurement network was established between 2001 and 2004 on 19 locations inside Spanish national parks and protected areas. The data collected suggest that ozone levels in mountainous areas are high enough to affect sensitive vegetation. Most of the locations registered moderate-to-high ozone levels, with important interannual variability. Altitudinal ozone gradients were observed in most of the parks with complex topography due to the establishment of local circulations that incorporate polluted air masses from polluted airsheds or even long-range transport (i.e., Canary Islands). Different latitude-dependent, yearly cycles were also observed, showing two, one, or no clear peaks depending on the region. These findings extend to the most southerly locations, except in the Canary Islands, where pollution transported from other regions in the upper transport layers probably led to the high concentrations observed.     

Natural environments,ancestral diets,and microbial ecology: is there a modern “paleo-deficit disorder”? Part I

Famed microbiologist René J. Dubos (1901–1982) was an early pioneer in the developmental origins of health and disease (DOHaD) construct. In the 1960s, he conducted groundbreaking experimental research concerning the ways in which early-life experience with nutrition, microbiota, stress, and other environmental variables could influence later-life health outcomes. He also wrote extensively on potential health consequences of a progressive loss of contact with natural environments (now referred to as green or blue space), arguing that Paleolithic experiences have created needs, particularly in the mental realm, that might not be met in the context of rapid global urbanization. He posited that humans would certainly adapt to modern urban landscapes and high technology, but there might be a toll to be paid in the form of higher psychological distress (symptoms of anxiety and depression) and diminished quality of life. In particular, there might be an erosion of humanness, exemplified by declines in altruism/empathy. Here in the first of a two-part review, we examine contemporary research related to natural environments and question to what extent Dubos might have been correct in some of his 50-year-old assertions.

“Human beings can almost certainly survive and multiply in the polluted cage of technological civilization, but we may sacrifice much of our humanness in adapting to such conditions…The maintenance of biological and mental health requires that technological societies provide in some form the biological freedom enjoyed by our Paleolithic ancestors”.Dr René Dubos, Invited Editorial, Life Magazine, 1970 [1].

     

Mortality,Causes of Death and Associated Factors Relate to a Large HIV Population-Based Cohort

Introduction

Antiretroviral therapy has led to a decrease in HIV-related mortality and to the emergence of non-AIDS defining diseases as competing causes of death. This study estimates the HIV mortality rate and their risk factors with regard to different causes in a large city from January 2001 to June 2013.

Materials and Methods

We followed-up 3137 newly diagnosed HIV non-AIDS cases. Causes of death were classified as HIV-related, non-HIV-related and external. We examined the effect of risk factors on survival using mortality rates, Kaplan-Meier plots and Cox models. Finally, we estimated survival for each main cause of death groups through Fine and Gray models.

Mortality Results

182 deaths were found [14.0/1000 person-years of follow-up (py); 95% confidence interval (CI):12.0–16.1/1000 py], 81.3% of them had a known cause of death. Mortality rate by HIV-related causes and non-HIV-related causes was the same (4.9/1000 py; CI:3.7–6.1/1000 py), external was lower [1.7/1000 py; (1.0–2.4/1000 py)].

Survival Results

Kaplan-Meier estimate showed worse survival in intravenous drug user (IDU) and heterosexuals than in men having sex with men (MSM). Factors associated with HIV-related causes of death include: IDU male (subHazard Ratio (sHR):3.2; CI:1.5–7.0) and <200 CD4 at diagnosis (sHR:2.7; CI:1.3–5.7) versus ≥500 CD4. Factors associated with non-HIV-related causes of death include: ageing (sHR:1.5; CI:1.4–1.7) and heterosexual female (sHR:2.8; CI:1.1–7.3) versus MSM. Factors associated with external causes of death were IDU male (sHR:28.7; CI:6.7–123.2) and heterosexual male (sHR:11.8; CI:2.5–56.4) versus MSM.

Conclusion and Recommendation

There are important differences in survival among transmission groups. Improved treatment is especially necessary in IDUs and heterosexual males.     

A functional connection between translation elongation and protein folding at the ribosome exit tunnel in Saccharomyces cerevisiae

Proteostasis needs to be tightly controlled to meet the cellular demand for correctly de novo folded proteins and to avoid protein aggregation. While a coupling between translation rate and co-translational folding, likely involving an interplay between the ribosome and its associated chaperones, clearly appears to exist, the underlying mechanisms and the contribution of ribosomal proteins remain to be explored. The ribosomal protein uL3 contains a long internal loop whose tip region is in close proximity to the ribosomal peptidyl transferase center. Intriguingly, the rpl3[W255C] allele, in which the residue making the closest contact to this catalytic site is mutated, affects diverse aspects of ribosome biogenesis and function. Here, we have uncovered, by performing a synthetic lethal screen with this allele, an unexpected link between translation and the folding of nascent proteins by the ribosome-associated Ssb-RAC chaperone system. Our results reveal that uL3 and Ssb-RAC cooperate to prevent 80S ribosomes from piling up within the 5′ region of mRNAs early on during translation elongation. Together, our study provides compelling in vivo evidence for a functional connection between peptide bond formation at the peptidyl transferase center and chaperone-assisted de novo folding of nascent polypeptides at the solvent-side of the peptide exit tunnel.     

Influence of proline on the thermostability of the active site and membrane arrangement of transmembrane proteins

Proline residues play a fundamental and subtle role in the dynamics, structure, and function in many membrane proteins. Temperature derivative spectroscopy and differential scanning calorimetry have been used to determine the effect of proline substitution in the structural stability of the active site and transmembrane arrangement of bacteriorhodopsin. We have analyzed the Pro-to-Ala mutation for the helix-embedded prolines Pro⁵⁰, Pro⁹¹, and Pro¹⁸⁶ in the native membrane environment. This information has been complemented with the analysis of the respective crystallographic structures by the FoldX force field. Differential scanning calorimetry allowed us to determine distorted membrane arrangement for P50A and P186A. The protein stability was severely affected for P186A and P91A. In the case of Pro⁹¹, a single point mutation is capable of strongly slowing down the conformational diffusion along the denaturation coordinate, becoming a barrier-free downhill process above 371 K. Temperature derivative spectroscopy, applied for first time to study thermal stability of proteins, has been used to monitor the stability of the active site of bacteriorhodopsin. The mutation of Pro⁹¹ and Pro¹⁸⁶ showed the most striking effects on the retinal binding pocket. These residues are the Pro in closer contact to the active site (activation energies for retinal release of 60.1 and 76.8 kcal/mol, respectively, compared to 115.8 kcal/mol for WT). FoldX analysis of the protein crystal structures indicates that the Pro-to-Ala mutations have both local and long-range effects on the structural stability of residues involved in the architecture of the protein and the active site and in the proton pumping function. Thus, this study provides a complete overview of the substitution effect of helix-embedded prolines in the thermodynamic and dynamic stability of a membrane protein, also related to its structure and function.     

New antibodies immobilization system into a graphite-polysulfone membrane for amperometric immunosensors

Polysulfone membrane is used for the first time for the preparation of electrochemical immunosensors. A disposable immunosensor based on a porous conductor polymer graphite-polysulfone-electrode has been developed using a phase inversion technique for the determination of anti-rabbit IgG (anti-RIgG) as a model analyte. To construct the sensor, a conductor membrane was deposited on the surface of working graphite-epoxy composite (GEC) electrode. The membrane was characterized by SEM. This sensor was based on the competitive assay between free and labeled anti-RIgG for the available binding sites of immobilized rabbit IgG (RIgG). Incubation parameters were optimized in this work. The immunological reaction was detected using an enzymatic-labeling procedure (HRP enzyme) combined with the amperometric detection using H(2)O(2) as substrate and hydroquinone as mediator. This sensor shows stability during a week and a good reproducibility. The current was monitored amperometrically at -0.1 V versus SCE and this method showed a linear range of the anti-RIgG from 1 to 6 microg/ml. The detection limit was determined to be 0.77 microg/ml.     

Using small-angle neutron scattering to study the solution conformation of N-(2-hydroxypropyl)methacrylamide copolymer-doxorubicin conjugates

Our past research developed two N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-doxorubicin (Dox) conjugates that became the first synthetic polymer-anticancer conjugates to be evaluated clinically. The first, FCE28068, contained Dox bound to the polymeric carrier via a tetrapeptidic linker (glycine-phenylalanine-leucine-glycine (GFLG)) (Mw approximately 30,000 g/mol; approximately 8 wt % drug), and the second, FCE28069, contained additionally galactosamine (Gal) (Mw approximately 30,000 g/mol; approximately 7.5 wt % Dox) again bound by a GFLG linker. Galactosamine was included to promote hepatocyte/hepatoma targeting via the asialoglycoprotein receptor. Both conjugates showed antitumor activity and were clinically less toxic than free Dox (2-5 fold). However, despite their similar chemical characteristics, the conjugates displayed a significantly different maximum-tolerated dose (MTD) in patients. The aim of this study, therefore, was to use small-angle neutron scattering (SANS) to explore the solution behavior of a small library of HPMA polymer conjugates including FCE28068, FCE28069, and their pharmaceutical formulations, plus as reference compounds HPMA copolymer-GFLG conjugates containing aminopropanol (Ap) or galactosamine (Gal) alone (i.e., without Dox). The SANS data obtained showed that HPMA copolymer-GFLG-Ap conjugates (containing 5 and 10 mol % side chains) showed evidence of polymer aggregation, however, no indication of aggregation was observed for FCE28068 and FCE28069 over the concentration range studied (2.5-50 mg/mL). Clear differences in the scattering behavior for the two conjugates were observed at equivalent concentration. Data were best fitted by a model for polydisperse Gaussian coils, and the HPMA copolymer-Dox conjugate with Gal (FCE28069) exhibited a larger radius of gyration (Rg) (by approximately 2.5 nm) compared to FCE28068. In conclusion, we have shown that SANS will be a valuable tool to elucidate conformation-performance relationships for polymer-drug conjugates.