Observing others: multiple action representation in the frontal lobe

Observation of actions performed by others activates monkey ventral premotor cortex, where action meaning, but not object identity, is coded. In a functional MRI (fMRI) study, we investigated whether other monkey frontal areas respond to actions performed by others. Observation of a hand grasping objects activated four frontal areas: rostral F5 and areas 45B, 45A, and 46. Observation of an individual grasping an object also activated caudal F5, which indicates different degrees of action abstraction in F5. Observation of shapes activated area 45, but not premotor F5. Convergence of object and action information in area 45 may be important for full comprehension of actions.     

High-probability uniquantal transmission at excitatory synapses in barrel cortex

The number of vesicles released at excitatory synapses and the number of release sites per synaptic connection are key determinants of information processing in the cortex, yet they remain uncertain. Here we show that the number of functional release sites and the number of anatomically identified synaptic contacts are equal at connections between spiny stellate and pyramidal cells in rat barrel cortex. Moreover, our results indicate that the amount of transmitter released per synaptic contact is independent of release probability and the intrinsic release probability is high. These properties suggest that connections between layer 4 and layer 2/3 are tuned for reliable transmission of spatially distributed, timing-based signals.     

Terrestrial ecosystem responses to species gains and losses

Ecosystems worldwide are losing some species and gaining others, resulting in an interchange of species that is having profound impacts on how these ecosystems function. However, research on the effects of species gains and losses has developed largely independently of one another. Recent conceptual advances regarding effects of species gain have arisen from studies that have unraveled the mechanistic basis of how invading species with novel traits alter biotic interactions and ecosystem processes. In contrast, studies on traits associated with species loss are fewer, and much remains unknown about how traits that predispose species to extinction affect ecological processes. Species gains and losses are both consequences and drivers of global change; thus, explicit integration of research on how both processes simultaneously affect ecosystem functioning is key to determining the response of the Earth system to current and future human activities.     

Recognition dynamics up to microseconds revealed from an RDC-derived ubiquitin ensemble in solution

Protein dynamics are essential for protein function, and yet it has been challenging to access the underlying atomic motions in solution on nanosecond-to-microsecond time scales. We present a structural ensemble of ubiquitin, refined against residual dipolar couplings (RDCs), comprising solution dynamics up to microseconds. The ensemble covers the complete structural heterogeneity observed in 46 ubiquitin crystal structures, most of which are complexes with other proteins. Conformational selection, rather than induced-fit motion, thus suffices to explain the molecular recognition dynamics of ubiquitin. Marked correlations are seen between the flexibility of the ensemble and contacts formed in ubiquitin complexes. A large part of the solution dynamics is concentrated in one concerted mode, which accounts for most of ubiquitin's molecular recognition heterogeneity and ensures a low entropic complex formation cost.     

Attitudes of European citizens towards pig production systems

The objective of the study is to map citizen attitudes towards pig meat production systems, and to investigate whether these attitudes associate with pork and pork product consumption. A conjoint experiment was carried out with empirical data collected from 1931 individuals in four European countries with higher-than-average per capita meat consumption (Belgium, Denmark, Poland and Germany). The experiment was based on the following pig farming characteristics: herd size, housing and floor type, efforts to reduce the impact of the production system on the environment, animal feed designed for producing pork with specific fat content, and finally the preferred quality characteristics of the pork end-product. The results of the conjoint analysis were used for a subsequent cluster analysis in order to identify European citizen clusters. Respondents' socio-demographic profile, attitudes towards issues that are expected to influence the way people evaluate pig meat production systems, and consumption frequency of various pork products are used as background information to identify segment profiles. Pork appears to play a substantial role as a part of the diet for most respondents in the four countries of this study. The results of the conjoint experiment at the sample level show that people assigned most importance to animal and environmental well-being as criteria to discriminate between “good” and “bad” pig production practices, despite the fact that their attitudes towards environmental protection, animal welfare and industrial food production were only moderately strong. Moreover, the results of the cluster analysis allowed small-sized, clear-cut clusters of citizens to appear, which pay attention to specific pig farming attributes. In conclusion, attitudes towards environment and nature, animal welfare and the need for an environment-friendly food production were indeed related to citizens' specific attitudes towards pig farming at the cluster level. However, the relationship between citizenship and consumption behaviour was found to be weak. What people think in their role as citizens related to pig production did not appear to significantly influence their pork consumption choices.     

ECOLOGICAL EFFECTS OF NITROGEN DEPOSITION ON URBAN FORESTS: AN OVERVIEW

The global urban area is expanding continuously, resulting in unprecedented emissions and deposition of reactive nitrogen(N) in urban environments.However, large knowledge gaps remain in the ecological effects of N deposition on urban forests that provide key ecosystem services for an increasing majority of city dwellers. The current understanding of the spatial patterns and ecological effects of N deposition in urban forests was synthesized based on a literature review of observational and expe...     

In Vitro Polymerization of Wheat Glutenin Subunits with Inorganic Oxidizing Agents. I. Comparison of Single‐Step and Stepwise Oxidations of High Molecular Weight Glutenin Subunits

High molecular weight glutenin subunits (HMW‐GS) were isolated from wheat flour and polymerized in vitro at pH 3.0 with different oxidizing agents (KBrO₃, KIO₃, H₂O₂). An oxidation protocol with single addition of oxidant (single‐step oxidation) was compared with a set‐up in which the oxidant was added in multiple steps (stepwise oxidation). Changes in size distribution were evaluated with size‐exclusion HPLC, multilayer SDS‐PAGE, and flow‐field flow fractionation (flow‐FFF). Flow‐FFF is particularly suitable for measuring changes in glutenin size in the very high size ranges. In order of increasing sizes of the resulting polymers, the different oxidizing agents could be ranked as KBrO₃ < KIO₃ < H₂O₂. However, none of the oxidation conditions allowed for a complete polymerization of HMW‐GS. Interestingly, it was found that high concentrations of KIO₃ negatively affect the degree of polymerization. A similar observation was not made with KBrO₃ or H₂O₂. SDS‐PAGE showed that y‐type HMW‐GS particularly failed to incorporate in glutenin polymers. Simultaneously, these HMW‐GS displayed higher mobilities on SDS‐PAGE that can be ascribed to the formation of intrachain SS bonds. Possible explanations for the incomplete polymerization of HMW‐GS are given.