Showing 3411 - 3420 of 5713 Items
Brutal Beauty: Paintings by Walton Ford
Date: 2000-01-01
Creator: Franklin Burroughs
Access: Open access
- "Catalog accompanies the exhibition of the same name at the Bowdoin College Museum of Art, Brunswick, Maine, September 29-December 10, 2000"--P. 2
Direct selection for sequences encoding proteases of known specificity
Date: 1991-06-15
Creator: Tracy A. Smith, Bruce D. Kohorn
Access: Open access
- We have developed a simple genetic selection that could be used to isolate eukaryotic cDNAs encoding proteases that cleave within a defined amino acid sequence. The selection was developed by using the transcription factor GAL4 from Saccharomyces cerevisiae as a selectable marker, a cloned protease from tobacco etch virus (TEV), and an 18-amino acid TEV protease target sequence. In yeast, TEV protease cleaves its target even when the target is fused to internal regions of the GAL4 protein. This cleavage separates the DNA binding domain from the transcription activation domain of GAL4, rendering it transcriptionally inactive. The proteolytic cleavage can be detected phenotypically by the inability of cells to metabolize galactose. Cells expressing the TEV protease can also be selected on the suicide substrate 2-deoxygalactose. DNA binding studies show that the TEV protease decreases the activity of the GAL4/target fusion protein. Because another protease target sequence of 55 amino acids can be inserted into GAL4 without any loss of transcriptional activity, this assay offers the opportunity to use high-efficiency cDNA cloning and expression vectors to select coding sequences of other proteases from various species. The assay could also be used to help define both target specificities and functional domains of proteases.
Two antisymmetric hypermultiplets in N = 2 SU(N) gauge theory: Seiberg-Witten curve and M-theory interpretation
Date: 1999-10-04
Creator: Isabel P. Ennes, Stephen G. Naculich, Henric Rhedin, Howard J. Schnitzer
Access: Open access
- The one-instanton contribution to the prepotential for N = 2 supersymmetric gauge theories with classical groups exhibits a universality of form. We extrapolate the observed regularity to SU (N) gauge theory with two antisymmetric hypermultiplets and Nf ≤ 3 hypermultiplets in the defining representation. Using methods developed for the instanton expansion of non-hyperelliptic curves, we construct an effective quartic Seiberg-Witten curve that generates this one-instanton prepotential. We then interpret this curve in terms of an M-theoretic picture involving NS 5-branes, D4-branes, D6-branes, and orientifold sixplanes, and show that for consistency, an infinite chain of 5-branes and orientifold sixplanes is required, corresponding to a curve of infinite order. © 1999 Elsevier Science B.V. All rights reserved.
Comparing enhancer action in cis and in trans
Date: 2012-08-01
Creator: Jack R. Bateman, Justine E. Johnson, Melissa N. Locke
Access: Open access
- Studies from diverse systems have shown that distinct interchromosomal interactions are a central component of nuclear organization. In some cases, these interactions allow an enhancer to act in trans, modulating the expression of a gene encoded on a separate chromosome held in close proximity. Despite recent advances in uncovering such phenomena, our understanding of how a regulatory element acts on another chromosome remains incomplete. Here, we describe a transgenic approach to better understand enhancer action in trans in Drosophila melanogaster. Using phiC31-based recombinase-mediated cassette exchange (RMCE), we placed transgenes carrying combinations of the simple enhancer GMR, a minimal promoter, and different fluorescent reporters at equivalent positions on homologous chromosomes so that they would pair via the endogenous somatic pairing machinery of Drosophila. Our data demonstrate that the enhancer GMR is capable of activating a promoter in trans and does so in a variegated pattern, suggesting stochastic interactions between the enhancer and the promoter when they are carried on separate chromosomes. Furthermore, we quantitatively assessed the impact of two concurrent promoter targets in cis and in trans to GMR, demonstrating that each promoter is capable of competing for the enhancer's activity, with the presence of one negatively affecting expression from the other. Finally, the single-cell resolution afforded by our approach allowed us to show that promoters in cis and in trans to GMR can both be activated in the same nucleus, implying that a single enhancer can share its activity between multiple promoter targets carried on separate chromosomes. © 2012 by the Genetics Society of America.
Adapting Greek Heroines: Penelope and Medea Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2020-01-01
Creator: Ishani Agarwal
Access: Access restricted to the Bowdoin Community
Wall-associated kinase 1 (WAK1) is crosslinked in endomembranes, and transport to the cell surface requires correct cell-wall synthesis
Date: 2006-06-01
Creator: Bruce D. Kohorn, Masaru Kobayashi, Sue Johansen, Henry Perry Friedman, Andy, Fischer, Nicole Byers
Access: Open access
- The Arabidopsis thaliana wall-associated kinases (WAKs) bind to pectin with an extracellular domain and also contain a cytoplasmic protein kinase domain. WAKs are required for cell elongation and modulate sugar metabolism. This work shows that in leaf protoplasts a WAK1-GFP fusion protein accumulates in a cytoplasmic compartment that contains pectin. The WAK compartment contains markers for the Golgi, the site of pectin synthesis. The migration of WAK1-GFP to the cell surface is far slower than that of a cell surface receptor not associated with the cell wall, is influenced by the presence of fucose side chains on one or more unidentified molecules that might include pectin, and is dependent upon cellulose synthesis on the plasma membrane. WAK is crosslinked into a detergent-insoluble complex within the cytoplasmic compartment before it appears on the cell surface, and this is independent of fucose modification or cellulose synthesis. Thus, the assembly and crosslinking of WAKs may begin at an early stage within a cytoplasmic compartment rather than in the cell wall itself, and is coordinated with synthesis of surface cellulose.
Re-formando cuerpos: Las identidades femeninas en escritoras cubanas durante el Período Especial
Date: 2014-01-01
Creator: Amanda M Montenegro
Access: Open access
- Esta tesis explora cómo una variedad de autoras cubanas representan el cuerpo, las identidades femeninas y la relación entre las mujeres y la nación. Las autoras estudiadas incluyen Marilyn Bobes, Karla Suárez y Daína Chaviano. Sus narrativas ilustran y desarrollan una variedad de personajes –desde las mujeres blancas prerrevolucionarias hasta las “hijas de la revolución” afrocubanas—que representan diferentes maneras en que las mujeres construyen y reconstruyen sus identidades en la Cuba revolucionaria y hasta el comienzo del “Período especial”. Ilustran además cómo las mujeres vivieron fenómenos propios de ese período como la migración, la dolarización y el jineterismo. Así, revelan los fracasos en cuanto a la igualdad de género de la revolución, que no transformó la estructura patriarcal de la sociedad. Sin embargo, las autoras presentan una nación cubana polifacética compuesta de más que el Estado, donde las escritoras y las mujeres luchan por definirse a sí mismas. This paper explores how various female Cuban authors represent the body, female identities and the relationship between women and the nation. The authors studied include Marilyn Bobes, Karla Suárez and Daína Chaviano. Their narratives illustrate and develop a variety of characters—ranging from white prerevolutionary women to afro-Cuban “daughters of the Revolution”—which represent different ways in which women construct and reconstruct their identities during revolutionary Cuba and at the beginning of the “Special Period.” The characters also illustrate how women in particular experienced and dealt with the effects of the Special Period such as migration, dollarization and jineterismo. Thus, they reveal the failures of the Cuban Revolution regarding gender equality of the Revolution, which did not transform the patriarchal structure of society. However, the authors present a multifaceted Cuban nation comprised of more than just the State, where writers and women struggle to define themselves.
An improved comparison of atmospheric Ar/N2 time series and paired ocean-atmosphere model predictions
Date: 2008-11-16
Creator: Nicolas Cassar, Galen A. McKinley, Michael L. Bender, Robert Mika, Mark, Battle
Access: Open access
- Ar/N2 variations in the atmosphere reflect ocean heat fluxes, air-sea gas exchange, and atmospheric dynamics. Here atmospheric Ar/N2 time series are compared to paired ocean-atmosphere model predictions. Agreement between Ar/N2 observations and simulations has improved in comparison to a previous study because of longer time series and the introduction of automated samplers at several of the atmospheric stations, as well as the refinement of the paired ocean-atmosphere models by inclusion of Ar and N2 as active tracers in the ocean component. Although analytical uncertainties and collection artifacts are likely to be mainly responsible for observed Ar/N2 outliers, air parcel back-trajectory analysis suggests that some of the variability in Ar/N2 measurements could be due to the low-altitude history of the air mass collected and, by extension, the local oceanic Ar/N2 signal. Although the simulated climatological seasonal cycle can currently be evaluated with Ar/N2 observations, longer time series and additional improvements in the signal-to-noise ratio will be required to test other model predictions such as interannual variability, latitudinal gradients, and the secular increase in atmospheric Ar/N2 expected to result from ocean warming. Copyright 2008 by the American Geophysical Union.