Structural basis for the molecular recognition between human splicing factors U2AF65 and SF1/mBBP

The essential splicing factors SF1 and U2AF play an important role in the recognition of the pre-mRNA 3' splice site during early spliceosome assembly. The structure of the C-terminal RRM (RRM3) of human U2AF(65) complexed to an N-terminal peptide of SF1 reveals an extended negatively charged helix A and an additional helix C. Helix C shields the potential RNA binding surface. SF1 binds to the opposite, helical face of RRM3. It inserts a conserved tryptophan into a hydrophobic pocket between helices A and B in a way that strikingly resembles part of the molecular interface in the U2AF heterodimer. This molecular recognition establishes a paradigm for protein binding by a subfamily of noncanonical RRMs.     

N-glycoproteomics in plants: perspectives and challenges

In eukaryotes, proteins that are secreted into the ER are mostly modified by N-glycans on consensus NxS/T sites. The N-linked glycan subsequently undergoes varying degrees of processing by enzymes which are spatially distributed over the ER and the Golgi apparatus. The post-ER N-glycan processing to complex glycans differs between animals and plants, with consequences for N-glycan and glycopeptide isolation and characterization of plant glycoproteins. Here we describe some recent developments in plant glycoproteomics and illustrate how general and plant specific technologies may be used to address different important biological questions.     

Effects of visual priming on taste-odor interaction

Little is known about the influence of visual characteristics other than colour on flavor perception, and the complex interactions between more than two sensory modalities. This study focused on the effects of recognizability of visual (texture) information on flavor perception of odorized sweet beverages. Participants rated the perceived sweetness of odorized sucrose solutions in the presence or absence of either a congruent or incongruent visual context. Odors were qualitatively reminiscent of sweet foods (strawberry and caramel) or not (savoury). Visual context was either an image of the same sweet foods (figurative context) or a visual texture derived from this product (non-figurative context). Textures were created using a texture synthesis method that preserved perceived food qualities while removing object information. Odor-taste combinations were rated sweeter within a figurative than a non-figurative context. This behaviour was exhibited for all odor-taste combinations, even in trials without images, indicating sustained priming by figurative visual context. A non-figurative context showed a transient sweetening effect. Sweetness was generally enhanced most by the strawberry odor. We conclude that the degree of recognizability of visual information (figurative versus non-figurative), influences flavor perception differently. Our results suggest that this visual context priming is mediated by separate sustained and transient processes that are differently evoked by figurative and non-figurative visual contexts. These components operate independent of the congruency of the image-odor-taste combinations.     

Neural correlates of visual aesthetics--beauty as the coalescence of stimulus and internal state

How do external stimuli and our internal state coalesce to create the distinctive aesthetic pleasures that give vibrance to human experience? Neuroaesthetics has so far focused on the neural correlates of observing beautiful stimuli compared to neutral or ugly stimuli, or on neural correlates of judging for beauty as opposed to other judgments. Our group questioned whether this approach is sufficient. In our view, a brain region that assesses beauty should show beauty-level-dependent activation during the beauty judgment task, but not during other, unrelated tasks. We therefore performed an fMRI experiment in which subjects judged visual textures for beauty, naturalness and roughness. Our focus was on finding brain activation related to the rated beauty level of the stimuli, which would take place exclusively during the beauty judgment. An initial whole-brain analysis did not reveal such interactions, yet a number of the regions showing main effects of the judgment task or the beauty level of stimuli were selectively sensitive to beauty level during the beauty task. Of the regions that were more active during beauty judgments than roughness judgments, the frontomedian cortex and the amygdala demonstrated the hypothesized interaction effect, while the posterior cingulate cortex did not. The latter region, which only showed a task effect, may play a supporting role in beauty assessments, such as attending to one''s internal state rather than the external world. Most of the regions showing interaction effects of judgment and beauty level correspond to regions that have previously been implicated in aesthetics using different stimulus classes, but based on either task or beauty effects alone. The fact that we have now shown that task-stimulus interactions are also present during the aesthetic judgment of visual textures implies that these areas form a network that is specifically devoted to aesthetic assessment, irrespective of the stimulus type.     

Analysis of protein mixtures from whole-cell extracts by single-run nanoLC-MS/MS using ultralong gradients

The majority of proteome-wide studies rely on the high separation power of two-dimensional liquid chromatography-tandem mass spectrometry (2D LC-MS/MS), often combined with protein prefractionation. Alternative approaches would be advantageous in order to reduce the analysis time and the amount of sample required. On the basis of the recent advances in chromatographic and mass spectrometric instrumentation, thousands of proteins can be identified in a single-run LC-MS/MS experiment using ultralong gradients. Consequently, the analysis of simple proteomes or clinical samples in adequate depth becomes possible by performing single-run LC-MS/MS experiments. Here we present a generally applicable protocol for protein analysis from unseparated whole-cell extracts and discuss its potential and limitations. Demonstrating the practical applicability of the method, we identified 2,761 proteins from a HeLa cell lysate, requiring around 10 h of nanoLC-MS/MS measurement time.     

Effects of temperature, relative humidity, absolute humidity, and evaporation potential on survival of airborne Gumboro vaccine virus

Survival of airborne virus influences the extent of disease transmission via air. How environmental factors affect viral survival is not fully understood. We investigated the survival of a vaccine strain of Gumboro virus which was aerosolized at three temperatures (10°C, 20°C, and 30°C) and two relative humidities (RHs) (40% and 70%). The response of viral survival to four metrics (temperature, RH, absolute humidity [AH], and evaporation potential [EP]) was examined. The results show a biphasic viral survival at 10°C and 20°C, i.e., a rapid initial inactivation in a short period (2.3 min) during and after aerosolization, followed by a slow secondary inactivation during a 20-min period after aerosolization. The initial decays of aerosolized virus at 10°C (1.68 to 3.03 ln % min(-1)) and 20°C (3.05 to 3.62 ln % min(-1)) were significantly lower than those at 30°C (5.67 to 5.96 ln % min(-1)). The secondary decays at 10°C (0.03 to 0.09 ln % min(-1)) tended to be higher than those at 20°C (-0.01 to 0.01 ln % min(-1)). The initial viral survival responded to temperature and RH and potentially to EP; the secondary viral survival responded to temperature and potentially to RH. In both phases, survival of the virus was not significantly affected by AH. These findings suggest that long-distance transmission of airborne virus is more likely to occur at 20°C than at 10°C or 30°C and that current Gumboro vaccination by wet aerosolization in poultry industry is not very effective due to the fast initial decay.     

Endogenous Price Bubbles in a Multi-Agent System of the Housing Market

Economic history shows a large number of boom-bust cycles, with the U.S. real estate market as one of the latest examples. Classical economic models have not been able to provide a full explanation for this type of market dynamics. Therefore, we analyze home prices in the U.S. using an alternative approach, a multi-agent complex system. Instead of the classical assumptions of agent rationality and market efficiency, agents in the model are heterogeneous, adaptive, and boundedly rational. We estimate the multi-agent system with historical house prices for the U.S. market. The model fits the data well and a deterministic version of the model can endogenously produce boom-and-bust cycles on the basis of the estimated coefficients. This implies that trading between agents themselves can create major price swings in absence of fundamental news.     

The Effect of Criticism on Functional Brain Connectivity and Associations with Neuroticism

Neuroticism is a robust personality trait that constitutes a risk factor for psychopathology, especially anxiety disorders and depression. High neurotic individuals tend to be more self-critical and are overly sensitive to criticism by others. Hence, we used a novel resting-state paradigm to investigate the effect of criticism on functional brain connectivity and associations with neuroticism. Forty-eight participants completed the NEO Personality Inventory Revised (NEO-PI-R) to assess neuroticism. Next, we recorded resting state functional magnetic resonance imaging (rsfMRI) during two sessions. We manipulated the second session before scanning by presenting three standardized critical remarks through headphones, in which the subject was urged to please lie still in the scanner. A seed-based functional connectivity method and subsequent clustering were used to analyse the resting state data. Based on the reviewed literature related to criticism, we selected brain regions associated with self-reflective processing and stress-regulation as regions of interest. The findings showed enhanced functional connectivity between the clustered seed regions and brain areas involved in emotion processing and social cognition during the processing of criticism. Concurrently, functional connectivity was reduced between these clusters and brain structures related to the default mode network and higher-order cognitive control. Furthermore, individuals scoring higher on neuroticism showed altered functional connectivity between the clustered seed regions and brain areas involved in the appraisal, expression and regulation of negative emotions. These results may suggest that the criticized person is attempting to understand the beliefs, perceptions and feelings of the critic in order to facilitate flexible and adaptive social behavior. Furthermore, multiple aspects of emotion processing were found to be affected in individuals scoring higher on neuroticism during the processing of criticism, which may increase their sensitivity to negative social-evaluation.