Physiological Functions of the COPI Complex in Higher Plants

COPI vesicles are essential to the retrograde transport of proteins in the early secretory pathway. The COPI coatomer complex consists of seven subunits, termed alpha-, beta-, beta'-, gamma-, delta-, epsilon-, and zeta-COP, in yeast and mammals. Plant genomes have homologs of these subunits, but the essentiality of their cellular functions has hampered the functional characterization of the subunit genes in plants. Here we have employed virus-induced gene silencing (VIGS) and dexamethasone (DEX)-inducible RNAI of the COPI subunit genes to study the in vivo functions of the COPI coatomer complex in plants. The beta'-, gamma-, and delta-COP subunits localized to the Golgi as GFP-fusion proteins and interacted with each other in the Golgi. Silencing of beta'-, gamma-, and delta-COP by VIGS resulted in growth arrest and acute plant death in Nicotiana benthamiana, with the affected leaf cells exhibiting morphological markers of programmed cell death. Depletion of the COPI subunits resulted in disruption of the Golgi structure and accumulation of autolysosome-like structures in earlier stages of gene silencing. In tobacco BY-2 cells, DEX-inducible RNAi of beta'-COP caused aberrant cell plate formation during cytokinesis. Collectively, these results suggest that COPI vesicles are essential to plant growth and survival by maintaining the Golgi apparatus and modulating cell plate formation.1196Ysciescopu

Magnetophoretic circuits for digital control of single particles and cells.

The ability to manipulate small fluid droplets, colloidal particles and single cells with the precision and parallelization of modern-day computer hardware has profound applications for biochemical detection, gene sequencing, chemical synthesis and highly parallel analysis of single cells. Drawing inspiration from general circuit theory and magnetic bubble technology, here we demonstrate a class of integrated circuits for executing sequential and parallel, timed operations on an ensemble of single particles and cells. The integrated circuits are constructed from lithographically defined, overlaid patterns of magnetic film and current lines. The magnetic patterns passively control particles similar to electrical conductors, diodes and capacitors. The current lines actively switch particles between different tracks similar to gated electrical transistors. When combined into arrays and driven by a rotating magnetic field clock, these integrated circuits have general multiplexing properties and enable the precise control of magnetizable objects

Oligonucleotide Functionalised Microbeads: Indispensable Tools for High-Throughput Aptamer Selection

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A systematic review of methods to measure family co-participation in physical activity.

The family environment is key in influencing children's health behaviours. Encouraging family co-participation in physical activity may therefore be an effective approach to increasing children's physical activity levels. Yet, little is known about how to best assess family co-participation in physical activity. This review summarizes methods to measure family co-participation in physical activity, which was defined as joint physical activities including at least one healthy child (0-18 years) and one other family member. Methods were identified through a systematic literature search, cross-referencing pre-selected reviews and contacting research groups. Thirty-seven measurement methods were included. Questionnaires were the most common method used, with the majority assessing frequency of co-participation and few also assessing duration and type. Reliability and internal consistency of scales were often reported, but rarely specified for the item(s) relevant to co-participation. Other methods of measuring co-participation included diaries, event history calendars, direct observations and accelerometry combined with diary, ecological momentary assessment or global positioning systems (GPS). Whilst a large number of measurement methods of family co-participation in physical activity exist, few are comprehensive and/or report acceptable psychometric properties. Future work should focus on reaching consensus in defining family co-participation in physical activity, and subsequently developing reliable and valid measures

Enhanced charge carrier transport properties in colloidal quantum dot solar cells via organic and inorganic hybrid surface passivation.

Colloidal quantum dots (CQDs) are extremely promising as photovoltaic materials. In particular, the tunability of their electronic band gap and cost effective synthetic procedures allow for the versatile fabrication of solar energy harvesting cells, resulting in optimal device performance. However, one of the main challenges in developing high performance quantum dot solar cells (QDSCs) is the improvement of the photo-generated charge transport and collection, which is mainly hindered by imperfect surface functionalization, such as the presence of surface electronic trap sites and the initial bulky surface ligands. Therefore, for these reasons, finding effective methods to efficiently decorate the surface of the as-prepared CQDs with new short molecular length chemical structures so as to enhance the performance of QDSCs is highly desirable. Here, we suggest employing hybrid halide ions along with the shortest heterocyclic molecule as a robust passivation structure to eliminate surface trap sites while decreasing the charge trapping dynamics and increasing the charge extraction efficiency in CQD active layers. This hybrid ligand treatment shows a better coordination with Pb atoms within the crystal, resulting in low trap sites and a near perfect removal of the pristine initial bulky ligands, thereby achieving better conductivity and film structure. Compared to halide ion-only treated cells, solar cells fabricated through this hybrid passivation method show an increase in the power conversion efficiency from 5.3% for the halide ion-treated cells to 6.8% for the hybrid-treated solar cells

Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution

Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system

Ezrin interacts with the SARS coronavirus spike protein and restrains infection at the entry stage

© 2012 Millet et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Entry of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) and its envelope fusion with host cell membrane are controlled by a series of complex molecular mechanisms, largely dependent on the viral envelope glycoprotein Spike (S). There are still many unknowns on the implication of cellular factors that regulate the entry process. Methodology/Principal Findings: We performed a yeast two-hybrid screen using as bait the carboxy-terminal endodomain of S, which faces the cytosol during and after opening of the fusion pore at early stages of the virus life cycle. Here we show that the ezrin membrane-actin linker interacts with S endodomain through the F1 lobe of its FERM domain and that both the eight carboxy-terminal amino-acids and a membrane-proximal cysteine cluster of S endodomain are important for this interaction in vitro. Interestingly, we found that ezrin is present at the site of entry of S-pseudotyped lentiviral particles in Vero E6 cells. Targeting ezrin function by small interfering RNA increased S-mediated entry of pseudotyped particles in epithelial cells. Furthermore, deletion of the eight carboxy-terminal amino acids of S enhanced S-pseudotyped particles infection. Expression of the ezrin dominant negative FERM domain enhanced cell susceptibility to infection by SARS-CoV and S pseudotyped particles and potentiated S-dependent membrane fusion. Conclusions/Significance: Ezrin interacts with SARS-CoV S endodomain and limits virus entry and fusion. Our data present a novel mechanism involving a cellular factor in the regulation of S-dependent early events of infection.This work was supported by the Research Grant Council of Hong Kong (RGC#760208)and the RESPARI project of the International Network of Pasteur Institutes

Host-Associated Bacteriophage Isolation and Preparation for Viral Metagenomics.

Prokaryotic viruses, or bacteriophages, are viruses that infect bacteria and archaea. These viruses have been known to associate with host systems for decades, yet only recently have their influence on the regulation of host-associated bacteria been appreciated. These studies have been conducted in many host systems, from the base of animal life in the Cnidarian phylum to mammals. These prokaryotic viruses are useful for regulating the number of bacteria in a host ecosystem and for regulating the strains of bacteria useful for the microbiome. These viruses are likely selected by the host to maintain bacterial populations. Viral metagenomics allows researchers to profile the communities of viruses associating with animal hosts, and importantly helps to determine the functional role these viruses play. Further, viral metagenomics show the sphere of viral involvement in gene flow and gene shuffling in an ever-changing host environment. The influence of prokaryotic viruses could, therefore, have a clear impact on host health

Design of a factorial experiment with randomization restrictions to assess medical device performance on vascular tissue

Background: Energy-based surgical scalpels are designed to efficiently transect and seal blood vessels using thermal energy to promote protein denaturation and coagulation. Assessment and design improvement of ultrasonic scalpel performance relies on both in vivo and ex vivo testing. The objective of this work was to design and implement a robust, experimental test matrix with randomization restrictions and predictive statistical power, which allowed for identification of those experimental variables that may affect the quality of the seal obtained ex vivo. Methods: The design of the experiment included three factors: temperature (two levels); the type of solution used to perfuse the artery during transection (three types); and artery type (two types) resulting in a total of twelve possible treatment combinations. Burst pressures of porcine carotid and renal arteries sealed ex vivo were assigned as the response variable. Results: The experimental test matrix was designed and carried out as a split-plot experiment in order to assess the contributions of several variables and their interactions while accounting for randomization restrictions present in the experimental setup. The statistical software package SAS was utilized and PROC MIXED was used to account for the randomization restrictions in the split-plot design. The combination of temperature, solution, and vessel type had a statistically significant impact on seal quality. Conclusions: The design and implementation of a split-plot experimental test-matrix provided a mechanism for addressing the existing technical randomization restrictions of ex vivo ultrasonic scalpel performance testing, while preserving the ability to examine the potential effects of independent factors or variables. This method for generating the experimental design and the statistical analyses of the resulting data are adaptable to a wide variety of experimental problems involving large-scale tissue-based studies of medical or experimental device efficacy and performance

Evaluations of Tactics for Automated Negotiations

[[abstract]]Automated negotiation under the infrastructure of e-commerce is becoming an important issue. However, although the communication protocols and frameworks of automated negotiation have been extensively investigated, the corresponding tactics and strategies are still underdeveloped and need to be evaluated further. Based on the negotiation model proposed by Faratin et al., this paper examines the performance of automated negotiation tactics and intends to provide concise suggestions for the users of automated negotiation. First, theoretical analysis is used to evaluate the behavior-dependent tactics. Constructive conclusions are obtained when single-issue negotiations are considered. Next, a new framework for applying single-issue tactics to multi-issue negotiation is proposed. Based on this framework, theoretical analysis is then extended to multi-issue cases. Finally, different from the previous work, exhaustive simulations based on two-issue negotiations are performed to evaluate the effectiveness of behavior-dependent and time-dependent tactics. The experimental results provide several important insights into negotiation tactics.[[booktype]]紙本[[booktype]]電子