Lipid Bilayers and Membrane Dynamics: Insight into Thickness Fluctuations

Thickness fluctuations have long been predicted in biological membranes but never directly observed experimentally. Here, we utilize neutron spin echo spectroscopy to experimentally reveal such fluctuations in a pure, fully saturated, phosphocholine lipid bilayer system. These fluctuations appear as an excess in the dynamics of undulation fluctuations. Like the bending rigidity, the thickness fluctuations change dramatically as the lipid transition temperature is crossed, appearing to be completely suppressed below the transition. Above the transition, the relaxation rate is on the order of 100 ns and is independent of temperature. The amplitude of the thickness fluctuations is $3.7 \AA ±0.7 \AA$, which agrees well with theoretical calculations and molecular dynamics simulations. The dependence of the fluctuations on lipid tail lengths is also investigated and determined to be minimal in the range of 14 to 18 carbon tails

Earlinet validation of CATS L2 product

The Cloud-Aerosol Transport System (CATS) onboard the International Space Station (ISS), is a lidar system providing vertically resolved aerosol and cloud profiles since February 2015. In this study, the CATS aerosol product is validated against the aerosol profiles provided by the European Aerosol Research Lidar Network (EARLINET). This validation activity is based on collocated CATS-EARLINET measurements and the comparison of the particle backscatter coefficient at 1064nm.Peer ReviewedPostprint (published version

Complete Genome Sequence of a New Firmicutes Species Isolated from Anaerobic Biomass Hydrolysis

A new Firmicutes isolate, strain HV4-6-A5C, was obtained from the hydrolysis stage of a mesophilic and anaerobic two-stage lab-scale leach-bed system for biomethanation of fresh grass. It is assumed that the bacterial isolate contributes to plant biomass degradation. Here, we report a draft annotated genome sequence of this organism. © 2017 Abendroth et al

Cell fueling and metabolic energy conservation in synthetic cells

We aim for a blue print for synthesizing complex subcellular systems from molecular components and ultimately for constructing life. Without comprehensive instructions and design principles we rely on simple reaction routes to operate the essential functions of life. The first forms of synthetic life will not make every building block for polymers de novo via complex pathways, rather they will be fed with amino acids, fatty acids and nucleotides. Controlled energy supply is crucial for any synthetic cell, no matter how complex. Here, we describe the simplest pathways for efficient generation of ATP and electrochemical ion gradients. We estimated the demand for ATP by polymer synthesis and maintenance processes in small cell-like systems, and we describe circuits to control the needs for ATP. We also present fluorescence-based sensors for pH, ionic strength, excluded volume, ATP/ADP, and viscosity, which allow monitoring and tuning of the major physicochemical conditions inside cells

Chiral imidazolium prolinate salts as efficient synzymatic organocatalysts for the asymmetric aldol reaction

Chiral imidazolium l-prolinate salts, providing a complex network of supramolecular interaction in a chiral environment, have been studied as synzymatic catalytic systems. They are demonstrated to be green and efficient chiral organocatalysts for direct asymmetric aldol reactions at room temperature. The corresponding aldol products were obtained with moderate to good enantioselectivities. The influence of the presence of chirality in both the imidazolium cation and the prolinate anion on the transfer of chirality from the organocatalyst to the aldol product has been studied. Moreover, interesting match/mismatch situations have been observed regarding configuration of chirality of the two components through the analysis of results for organocatalysts derived from both enantiomers of prolinate (R/S) and the trans/cis isomers for the chiral fragment of the cation. This is associated with differences in the corresponding reaction rates but also to the different tendencies for the formation of aggregates, as evidenced by nonlinear effects studies (NLE). Excellent activities, selectivities, and enantioselectivities could be achieved by an appropriate selection of the structural elements at the cation and anion

Leaf carotenoid concentrations and monoterpene emission capacity under acclimation of the light reactions of photosynthesis

Factors controlling the seasonal dynamics (days-weeks) in leaf monoterpene emission capacity are not yet well understood. Volatile isoprenoids, such as monoterpenes, and higher isoprenoids such as carotenoids share the initial steps of their synthesis pathways, therefore, interaction between the pool size of leaf carotenoids and its acclimation and leaf monoterpene emission capacity could be expected. Our aim was to examine this interaction in evergreen foliage using the non-storing Holm oak (Quercus ilex L.), as a model species. We modified the light environment of a number of potted trees in order to induce acclimation in leaf carotenoid contents, and study the effects on leaf monoterpene emission capacity. We followed chlorophyll fluorescence, photosynthetic capacity, chlorophyll and carotenoid contents, and monoterpene emission capacity. The results indicate that monoterpene emission capacity and photosynthetic pigment metabolism are coupled in Holm oak seedlings growing at or acclimating to different light levels

Measurement of glucose exclusion from the fully hydrated DOPE inverse hexagonal phase

The degree of exclusion of glucose from the inverse hexagonal HII phase of fully hydrated DOPE is determined using contrast variation small angle neutron scattering and small angle X-ray scattering. The presence of glucose is found to favour the formation of the non-lamellar HII phase over the fluid lamellar phase, over a wide range of temperatures, while having no significant effect on the structure of the HII phase. Glucose is preferentially excluded from the lipid-water interface resulting in a glucose concentration in the HII phase of less than half that in the coexisting aqueous phase. The degree of exclusion is quantified and the results are consistent with a hydration layer of pure water adjacent to the lipid head groups from which glucose is excluded. The osmotic gradient created by the difference in glucose concentration is determined and the influence of glucose on the phase behaviour of non-lamellar phase forming lipid systems is discussed

Vínculos familiares e inclusión social. Variables predictoras de la conducta prosocial en la infancia

The purpose of this study was to investigate the relationship between prosocial behavior and family environment variables (attachment to the mother and father and abandonment by the mother and father), personal variables (emotional instability, aggression, and coping strategies), and variables that relate to the immediate social environment (peer acceptance and rejection). This study also examined the predictors of prosocial behavior. Prosocial behavior is a personal protective factor that encourages positive relationships between peers and promotes personal and social adjustment behaviors (Mikolajewski, Chavarria, Moltisanti, Hart & Taylor, 2014). A study with a sample of 1,447 children (50.4% male and 49.6% female) aged between 7 and 12 years (M = 9.27; SD = 1.36) was conducted. The results confirmed the positive relationships between prosocial behavior and parental attachment, functional coping, and peer acceptance. The results also confirmed the negative relationships between prosocial behavior and abandonment by the parents, emotional instability, aggression, dysfunctional coping, and peer rejection. The positive predictor variables for prosocial behavior were attachment to the mother, functional coping, and expectations of peer acceptance. The negative predictor variables for prosocial behavior were emotional instability, physical and verbal aggression, and expectations of peer rejection. The findings have educational implications, which are discussed herein.Los objetivos de esta investigación son analizar las relaciones de la conducta prosocial con variables del entorno familiar (apego y abandono del padre y de la madre), variables personales (inestabilidad emocional, agresividad y afrontamiento ante situaciones estresantes) y variables del entorno social próximo (aceptación y rechazo por los pares); además, estudiar las variables predictoras de la conducta prosocial. La conducta prosocial constituye un factor de protección personal que fomenta relaciones positivas entre los pares y promueve comportamientos de adaptación personal y social (Mikolajewski, Chavarria, Moltisanti, Hart y Taylor, 2014). Han participado 1447 niños/as (50.4% varones y 49.6% mujeres). Tienen entre 7 y 12 años (M=9.27 y SD= 1.36). Los resultados comprueban las relaciones positivas de la conducta prosocial con apego (padre y madre), afrontamiento funcional y aceptación por los pares. Asimismo, muestran las relaciones negativas de la conducta prosocial con abandono (padre y madre), inestabilidad emocional, agresividad, afrontamiento disfuncional y rechazo por los pares. Las variables predictoras de la conducta prosocial son, en positivo, apego de la madre, afrontamiento funcional y expectativas de aceptación por los pares; y, en negativo, son inestabilidad emocional, agresividad física y verbal, y expectativas de rechazo por los pares. Se discuten las implicaciones educativas