Ligand and membrane-binding behavior of the phosphatidylinositol transfer proteins PITPα and β

Phosphatidylinositol transfer proteins (PITPs) are believed to be lipid transfer proteins due to their ability to transfer either PI or PC between membrane compartments in vitro. However, the detailed mechanism of this transfer process is not fully established. To further understand the transfer mechanism of PITPs we examined the interaction of PITPs with membranes using dual polarization interferometry (DPI) which measures protein binding affinity on a flat immobilized lipid surface. In addition, a fluorescence resonance energy transfer (FRET)-based assay was also employed to monitor how quickly PITPs transfer their ligands to lipid vesicles. DPI analysis revealed that PITPβ had a higher affinity to membranes compared to PITPα. Furthermore, the FRET-based transfer assay revealed that PITPβ has a higher ligand transfer rate compared to PITPα. However, both PITPα and PITPβ demonstrated a preference for highly curved membrane surfaces during ligand transfer. In other words, ligand transfer rate was higher when the accepting vesicles were highly curved

A large-scale field experiment on salt marsh construction

Salt marshes provide important natural habitats, mitigate effects of subsidence and sea level rise and help in coastal defence. Commissioned by the municipality of Delfzijl, the EcoShape consortium obtained the opportunity to carry out a large-scale field experiment on salt marsh construction as part of their Living Lab for MUD

Balancing food and density-dependence in the spatial distribution of an interference-prone forager

Foraging distributions are thought to be density-dependent, because animals not only select for a high availability and quality of resources, but also avoid conspecific interference. Since these processes are confounded, their relative importance in shaping foraging distributions remains poorly understood. Here we aimed to rank the contribution of density-dependent and density-independent effects on the spatio-temporal foraging patterns of eurasian oystercatchers. In our intertidal study area, tides caused continuous variation in oystercatcher density, providing an opportunity to disentangle conspecific interference and density-independent interactions with the food landscape. Spatial distributions were quantified using high-resolution individual tracking of foraging activity and location. In a model environment that included a realistic reconstruction of both the tides and the benthic food, we tested a family of behaviour-based optimality models against these tracking data. Density-independent interactions affected spatial distributions much more strongly than conspecific interference, even in an interference-prone species like oystercatchers. Spatial distributions were governed by avoidance of bill injury costs, selection for high interference-free intake rates and a decreasing availability of benthic bivalve prey after their exposure. These density-independent interactions outweighed interference competition in terms of effect size. We suggest that the bottleneck in our mechanistic understanding of foraging distributions may be primarily the role of density-independent prey attributes unrelated to intake rates, like damage costs in the case of oystercatchers foraging on perilous prey. At a landscape scale, above the finest inter-individual distances, effects of conspecific interaction on spatial distributions may have been overemphasised

A comparison of the early motor repertoire of very preterm infants and term infants

OBJECTIVE: To obtain reference data on the early motor repertoire of very preterm infants compared with healthy term infants at three months' post-term age. STUDY DESIGN: In this observational study, using Prechtl's method on the assessment of the early motor repertoire, we compared the quality of fidgety movements and the concurrent motor optimality score - revised of infants with a gestational age <30 weeks and/or a birth weight <1000 g with healthy infants with a gestational age of 37-42 weeks. RESULTS: One hundred eighty very preterm and 180 healthy term infants participated. The median motor optimality scores - revised of very preterm infants were significantly lower in comparison to those of term infants, with scores of 24 (25th-75th percentiles: 23-26) and 26 (25th-75th percentiles: 26-28), respectively. Fidgety movements were aberrant (abnormal or absent) more often in very preterm infants than in term infants. The odds ratio was 4.59 (95% CI, 1.51-13.92). Compared with term infants, very preterm infants had poorer scores on the subscales age-adequate movement repertoire, observed postural patterns, and movement character with odds ratios ≥2.97. We found no differences regarding observed movement patterns. CONCLUSION: This study provides reference data on the early motor repertoire of very preterm and healthy term infants. It demonstrates that the early motor repertoire of very preterm infants is poorer than that of term infants, a finding consistent with existing knowledge that prematurity increases the risk of poor neurodevelopment

A Capsid-Encoded PPxY-Motif Facilitates Adenovirus Entry

Viruses use cellular machinery to enter and infect cells. In this study we address the cell entry mechanisms of nonenveloped adenoviruses (Ads). We show that protein VI, an internal capsid protein, is rapidly exposed after cell surface attachment and internalization and remains partially associated with the capsid during intracellular transport. We found that a PPxY motif within protein VI recruits Nedd4 E3 ubiquitin ligases to bind and ubiquitylate protein VI. We further show that this PPxY motif is involved in rapid, microtubule-dependent intracellular movement of protein VI. Ads with a mutated PPxY motif can efficiently escape endosomes but are defective in microtubule-dependent trafficking toward the nucleus. Likewise, depletion of Nedd4 ligases attenuates nuclear accumulation of incoming Ad particles and infection. Our data provide the first evidence that virus-encoded PPxY motifs are required during virus entry, which may be of significance for several other pathogens

The Short-term Car Flow Planning Model in Rail Freight Company – Case Study

AbstractWith the promotion of the environmentally friendly transportation modes (the European Commission supports the freight transport operations in the rail sector), an increase in the diversification of the demand is observed. While most rail freight companies tend to apply fixed schedules, this approach is not effective turns out to be ineffective due to the need to meet the customer's specific requirements.The purpose of this paper is to present a case study of empty wagon flow planning over a medium term horizon and to discuss the opportunities of improvement of this plans by discrete optimization. In order to increase the utilization and availability of wagons, the planning procedure with a rolling horizon has to be implemented. Unfortunately, since the plan has to be updated ca. every 4hours, this planning approach needs effective optimization tools. Our hybrid two-stage approach is designed to be implemented in such business environment. This formulation allows us to solve real life instances even for a 7-day time horizon

The teaching of recent and violent conflicts as challenges for history education

This paper has been written with the support of Projects EDU2015-65088P from the DGICYT (Ministry of Education, Spain) and also the Project PICT2012-1594 from the ANPCYT (Argentina) coordinated by the autho

Perspectief natuurlijke keringen: een eerste verkenning ten behoeve van het Deltaprogramma

In het Deltaprogramma staan de waterveiligheid en de watervoorziening van Nederland nu en voor de lange termijn centraal. In de aanpak wordt actief gezocht naar de koppeling met andere ambities van rijk, provincies, waterschappen, gemeenten, maar ook van maatschappelijke organisaties en bedrijven op andere beleidsterreinen, zoals economie, natuur en ruimte. De Deltacommissaris heeft de Stichting Ecoshape gevraagd de mogelijkheden te verkennen voor het toepassen van natuurlijke keringen in het IJsselmeergebied, de Wadden en estuaria en het rivierengebie