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Complex Composition (complex + composition)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

A combinatorial approach to studying protein complex composition by employing size-exclusion chromatography and proteome analysis

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 10 2007
Shi-Sheng Li
Abstract The genome sequences of numerous organisms are available now, but gene sequences alone do not provide sufficient information to accurately deduce protein functions. Protein function is largely dependent on the association of multiple polypeptide chains into large structures with interacting subunits that regulate and support each other. Therefore, the mapping of protein interaction networks in a physiological context is conducive to deciphering protein functions, including those of hypothetical proteins. Although several high-throughput methods to globally identify protein interactions have been reported in recent years, these approaches often have a high rate of nonspecific or artificial interactions detected. For instance, the fraction of false positives of the protein interactions identified by yeast two-hybrid assay has been predicted to be of the order of 50%. We have developed a strategy to globally map Bacillus subtilis protein,protein interactions in a physiological context by fractionating the cell lysates using size-exclusion chromatography (SEC), followed by proteome analysis. Components of both known and unknown protein complexes, multisubunits and multiproteins, have been identified using this strategy. In one case, the partners of the B. subtilis protein complex have been coexpressed in Escherichia coli, and the formation of the overexpressed protein complex has been further confirmed by a pull-down assay. [source]

Class in the Classroom: Engaging Hidden Identities

METAPHILOSOPHY, Issue 4 2001
Peter W. Wakefield
Using Marcuse's theory of the total mobilization of advanced technology society along the lines of what he calls "the performance principle," I attempt to describe the complex composition of class oppression in the classroom. Students conceive of themselves as economic units, customers pursuing neutral interests in a morally neutral, socio-economic system of capitalist competition. The classic, unreflective conception of the classroom responds to this by implicitly endorsing individualism and ideals of humanist citizenship. While racism and cultural diversity have come to count as elements of liberal intelligence in most college curricula, attempts to theorize these aspects of social and individual identity and place them in a broader content of class appear radical and inconsistent with the humanistic notion that we all have control over who we are and what we achieve. But tags such as "radical" and "unrealistic" mark a society based on the performance principle. Marcuse allows us to recognize a single author behind elements of psychology, metaphysics, and capitalism. The fact that bell hooks hits upon a similar notion suggests that we might use Marcuse's theory of the truly liberatory potential of imagination to transform and reconceive our classrooms so that the insidious effects of class, racism, and individualistic apathy might be subverted. Specifically, I outline and place into this theoretical context three concrete pedagogical practices: (a) the use of the physical space of the classroom; (b) the performance of community through group readings and short full-class ceremonies, and (c) the symbolic modeling represented by interdisciplinary approaches to teaching. All three of these practices engage students in ways that co-curricularly subvert class (and, incidentally, race divisions) and allow students to imagine, and so engage in, political action for justice as they see it. [source]

Differential expression of polycomb repression complex 1 (PRC1) members in the developing mouse brain reveals multiple complexes

DEVELOPMENTAL DYNAMICS, Issue 9 2006
Tanja Vogel
Abstract Polycomb group (PcG) genes are regulators of body segmentation and cell growth, therefore being important players during development. PcG proteins form large complexes (PRC) that fulfil mostly repressive regulative functions on homeotic gene expression. Although expression of PcG genes in the brain has been noticed, the involvement of PcG genes in the processes of brain development is not understood. In this study, we analysed the expression patterns of PRC1 complex members to reveal PcG proteins that might be relevant for mouse brain development. Using in situ hybridisation, we show PRC1 activity in proliferative progenitor cells during neurogenesis, but also in maturated neuronal structures. PRC1 complex compositions vary in a spatial and temporal controlled manner during mouse brain development, providing cellular tools to act in different developmental contexts of cell proliferation, cell fate determination, and differentiation. Developmental Dynamics 235:2574,2585, 2006. © 2006 Wiley-Liss, Inc. [source]

Controlled Assembly of Au, Ag, and Pt Nanoparticles with Chitosan

CHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2009
Min Hong
Abstract Working on the chain gang: A simple method for the controlled assembly of metal nanoparticles (Au, Ag, and Pt) into 1D chains (see figure) has been developed based on the electrostatic interaction of negatively charged carboxylic groups on the citrate ions surrounding the NPs and the positively charged chitosan polymer. A simple method for the controlled assembly of metal nanoparticles into one-dimensional chains has been developed. The chain-formation process could be accounted for by the electrostatic interaction of the negatively charged carboxylic groups on the citrate ions surrounding metal nanoparticles and the positively charged chitosan polymer. Three representative types of nanoparticles comprising Au, Ag, and Pt, respectively, have been used to illustrate the generic applicability of the proposed methodology. Facile control of the chain length of the nanoparticle assembly could be achieved by adjusting the concentrations of negatively or positively charged species. We anticipate the ready adaptability of the methodology to nanoparticles of more complex compositions. [source]