An Arabidopsis rhomboid protease has roles in the chloroplast and in flower development

Increasing numbers of cellular pathways are now recognized to be regulated via proteolytic processing events. The rhomboid family of serine proteases plays a pivotal role in a diverse range of pathways, activating and releasing proteins via regulated intramembrane proteolysis. The prototype rhomboid protease, rhomboid-1 in Drosophila, is the key activator of epidermal growth factor (EGF) receptor pathway signalling in the fly and thus affects multiple aspects of development. The role of the rhomboid family in plants is explored and another developmental phenotype, this time in a mutant of an Arabidopsis chloroplast-localized rhomboid, is reported here. It is confirmed by GFP-protein fusion that this protease is located in the envelope of chloroplasts and of chlorophyll-free plastids elsewhere in the plant. Mutant plants lacking this organellar rhomboid demonstrate reduced fertility, as documented previously with KOM—the one other Arabidopsis rhomboid mutant that has been reported in the literature—along with aberrant floral morphology

Proposed methods for reviewing the outcomes of health research: the impact of funding by the UK's Arthritis Research Campaign

Background: External and internal factors are increasingly encouraging research funding bodies to demonstrate the outcomes of their research. Traditional methods of assessing research are still important, but can be merged into broader multi-dimensional categorisations of research benefits. The onus has hitherto been on public sector funding bodies, but in the UK the role of medical charities in funding research is particularly important and the Arthritis Research Campaign, the leading medical charity in its field in the UK, commissioned a study to identify the outcomes from research that it funds. This article describes the methods to be used. Methods: A case study approach will enable narratives to be told, illuminating how research funded in the early 1990s was (or was not) translated into practice. Each study will be organised using a common structure, which, with careful selection of cases, should enable cross-case analysis to illustrate the strengths of different modes and categories of research. Three main interdependent methods will be used: documentary and literature review; semi-structured interviews; and bibliometric analysis. The evaluative framework for organising the studies was previously used for assessing the benefits from health services research. Here, it has been specifically amended for a medical charity that funds a wide range of research and is concerned to develop the careers of researchers. It was further refined in three pilot studies. The framework has two main elements. First, a multi-dimensional categorisation of benefits going from the knowledge produced in peer reviewed journal articles through to the health and potential economic gain. The second element is a logic model, which, with various stages, should provide a way of organising the studies. The stock of knowledge is important: much research, especially basic, will feed into it and influence further research rather than directly lead to health gains. The cross-case analysis will look for factors associated with outcomes. Conclusions: The pilots confirmed the applicability of the methods for a full study which should assist the Arthritis Research Campaign to demonstrate the outcomes from its funding, and provide it with evidence to inform its own policies

Photosynthetic Adaptation to Length of Day Is Dependent on S-Sulfocysteine Synthase Activity in the Thylakoid Lumen

Arabidopsis (Arabidopsis thaliana) chloroplasts contain two O-acetyl-serine(thiol)lyase (OASTL) homologs, OAS-B, which is an authentic OASTL, and CS26, which has S-sulfocysteine synthase activity. In contrast with OAS-B, the loss of CS26 function resulted in dramatic phenotypic changes, which were dependent on the light treatment. We have performed a detailed characterization of the photosynthetic and chlorophyll fluorescence parameters in cs26 plants compared with those of wild-type plants under short-day growth conditions (SD) and long-day growth conditions (LD). Under LD, the photosynthetic characterization, which was based on substomatal CO2 concentrations and CO2 concentration in the chloroplast curves, revealed significant reductions in most of the photosynthetic parameters for cs26, which were unchanged under SD. These parameters included net CO2 assimilation rate, mesophyll conductance, and mitochondrial respiration at darkness. The analysis also showed that cs26 under LD required more absorbed quanta per driven electron flux and fixed CO2. The nonphotochemical quenching values suggested that in cs26 plants, the excess electrons that are not used in photochemical reactions may form reactive oxygen species. A photoinhibitory effect was confirmed by the background fluorescence signal values under LD and SD, which were higher in young leaves compared with mature ones under SD. To hypothesize the role of CS26 in relation to the photosynthetic machinery, we addressed its location inside of the chloroplast. The activity determination and localization analyses that were performed using immunoblotting indicated the presence of an active CS26 enzyme exclusively in the thylakoid lumen. This finding was reinforced by the observation of marked alterations in many lumenal proteins in the cs26 mutant compared with the wild type.Peer Reviewe

Social Media and the Democratization of American Museums

The democratization of American museums has been accelerated by societal changes caused by the development of new, multiway channels of communication created by the Internet and social media. Social media is prompting public participa- tion which has led to a paradigm shift in museology towards public engagement. The rise of vernacular creativity, especially among the younger, digitally native generations who are “curating” their identities by replicating, manipulating and sharing culture on- line, challenges the authority of the museum and curator as arbiters of culture. This paradigm shift also broadens the definition of authenticity from the object to the au- thentic experience. This paper argues that museums have a responsibility to remain relevant and to model the use of new technologies in the service of public good and in the pursuit of democratic ideals. They can only do so through nimble experimentation with social media. An examination of the evolution of the museum’s role in American society is followed by an analysis of the impact of technology on museum practice and philosophy. The description of a number of case studies involving social media initia- tives by museums suggests that engaging the public in the curatorial process throughcrowd-sourced and crowd-curated exhibitions may be the key to museum sustain- ability. Finally, an outline of a social media campaign designed for an exhibition at the University of San Francisco’s Thacher Gallery, co-curated by the M.A. in Museum Studies Curatorial Practicum serves as a lesson in the use of the new media platform,Instagram

2008 Progress Report on Brain Research

Highlights new research on various disorders, nervous system injuries, neuroethics, neuroimmunology, pain, sense and body function, stem cells and neurogenesis, and thought and memory. Includes essays on arts and cognition and on deep brain stimulation

Structural and functional basis for lipid synergy on the activity of the antibacterial peptide ABC transporter McjD

The lipid bilayer is a dynamic environment that consists of a mixture of lipids with different properties that regulate the function of membrane proteins; these lipids are either annular, masking the protein hydrophobic surface, or specific lipids, essential for protein function. In this study, using tandem mass spectrometry, we have identified specific lipids associated with the Escherichia coli ABC transporter McjD, which translocates the antibacterial peptide MccJ25. Using non-denaturing mass spectrometry, we show that McjD in complex with MccJ25 survives the gas-phase. Partial delipidation of McjD resulted in reduced ATPase activity and thermostability as shown by Circular Dichroism, both of which could be restored upon addition of defined E. coli lipids. We have resolved a phosphatidylglycerol lipid associated with McjD at 3.4 Å resolution, while molecular dynamic simulations carried out in different lipid environments assessed the binding of specific lipids to McjD. Combined, our data show a synergistic effect of zwitterionic and negatively charged lipids on the activity of McjD; the zwitterionic lipids provide structural stability to McjD whereas the negatively charged lipids are essential for its function

The efficacy of homogeneous groups in enhancing individual learning

One possible enhancement to improving both the teaching and the learning process is an appropriate design of a learning environment. Collaborative learning, if appropriately used, has been one such tool that has been known to benefit learners. An issue that needs to be addressed, and one that can affect individual learning is the nature of the group composition in a collaborative environment. This paper analyzes the results of an experiment that was conducted on a module in a computer science degree course. The study sought to find the relevance of group composition to the amount of individual student learning. The underlying pedagogical approach for this activity is a collaborative learning experience through team work using heterogeneous and homogeneous groups.The analysis reveals a significant improvement in individual student performance in the year the groups were made homogenous. Keywords: collaborative learning, improving classroom teaching, pedagogical issues, teaching/learning strategies, computer science education

Novel Proteins Involved in Dynamics of The Photosynthetic Apparatus

During the past few years, a considerable number of research articles have been published relating to the structure and function of the major photosynthetic protein complexes, photosystem (PS) I, PSII, cytochrome (Cyt) b6f, and adenosine triphosphate (ATP) synthase. Sequencing of the Arabidopsis thaliana (Arabidopsis) genome together with several high-quality proteomics studies has, however, revealed that the thylakoid membrane network of plant chloroplasts still contains a number of functionally unknown proteins. These proteins may have a role as auxiliary proteins guiding the assembly, maintenance, and turnover of the thylakoid protein complexes, or they may be as yet unknown subunits of the photosynthetic complexes. Novel subunits are most likely to be found in the NAD(P)H dehydrogenase (NDH) complex, the structure and function of which have remained obscure in the absence of detailed crystallographic data, thus making this thylakoid protein complex a particularly interesting target of investigation. In this thesis, several novel thylakoid-associated proteins were identified by proteomics-based methods. The major goal of characterization of the stroma thylakoid associated polysome-nascent chain complexes was to determine the proteins that guide the dynamic life cycle of PSII. In addition, a large protein complex of ≥ 1,000 kDa, residing in the stroma thylakoid, was characterized in greater depth and it was found to be a supercomplex composed of the PSI and NDH complexes. A set of newly identified proteins from Arabidopsis thylakoids was subjected to detailed characterization using the reverse genetics approach and extensive biochemical and biophysical analysis. The role of the novel proteins, either as auxiliary proteins or subunits of the photosynthetic protein complexes, was revealed. Two novel thylakoid lumen proteins, TLP18.3 and AtCYP38, function as auxiliary proteins assisting specific steps of the assembly/repair of PSII. The role of the 10-kDa thylakoid lumen protein PsbR is related to the optimization of oxygen evolution of PSII by assisting the assembly of the PsbP protein. Two integral thylakoid membrane proteins, NDH45 and NDH48, are novel subunits of the chloroplast NDH complex. Finally, the thylakoid lumen immunophilin AtCYP20-2 is suggested to interact with the NDH complex, instead of PSII as was hypothesized earlier.Siirretty Doriast

Isaiah Horowitz’s Shenei Luhot Haberit (Shelah): A Vision of Jewish Pietism

This thesis provides the first comprehensive analysis of Isaiah Horowitz's 1649 magnum opus, the Shenei Luhot Haberit (Shelah) and its contribution towards Jewish Thought. Horowitz's work is an 844-paged encyclopaedia which presents the mystical kabbalah as the authoritative philosophy of Judaism, explaining how it informs all other areas of Jewish Thought. In this manner, Horowitz reinterpreted classical Jewish beliefs along kabbalistic lines and developed a concept of Jewish Orthodoxy 200 years before the term became widespread. Horowitz's contribution towards Jewish mysticism is best understood as a reconfiguration of esoteric concepts into ordinary modes of behaviour: unlike his kabbalistic predecessors, Horowitz argued that mystical union with God is achieved through everyday activities and not exclusively through extraordinary meditative states. Furthermore, Horowitz broke with the time-honoured separation between the legal and mystical spheres by showing how kabbalah is necessary in order to decide matters of Jewish law. By inserting many kabbalistic customs into the Shelah and conferring texts such as the Zohar with authoritative legal status, Horowitz directed Ashkenazic Judaism along kabbalistic lines in the 17th century. Horowitz also cultivated an ethos of pietism which emphasised world-affirmation and joy: two dominant themes in the Shelah are that every Jew can serve God through sanctifying the material world and that religious conduct is empty without passion and enthusiasm. This culminates in an eschatological vision where the messiah will arrive after the realm of evil has been purified through personal and national transformation. The Shelah was a highly influential work, and this study provides an important aid for scholars trying to understand the intellectual and religious development of diffuse Jewish movements ranging from the Sabbateans in the 17th century, the Hasidism and their opponents in the 18th century and the Orthodox in the 19th century