The Skn7 Response Regulator of \u3ci\u3eSaccharomyces cerevisiae\u3c/i\u3e Interacts with Hsf1 In Vivo and Is Required for the Induction of Heat Shock Genes by Oxidative Stress

The Skn7 response regulator has previously been shown to play a role in the induction of stress-responsive genes in yeast, e.g., in the induction of the thioredoxin gene in response to hydrogen peroxide. The yeast Heat Shock Factor, Hsf1, is central to the induction of another set of stress-inducible genes, namely the heat shock genes. These two regulatory trans-activators, Hsf1 and Skn7, share certain structural homologies, particularly in their DNA-binding domains and the presence of adjacent regions of coiled-coil structure, which are known to mediate protein–protein interactions. Here, we provide evidence that Hsf1 and Skn7 interact in vitro and in vivo and we show that Skn7 can bind to the same regulatory sequences as Hsf1, namely heat shock elements. Furthermore, we demonstrate that a strain deleted for the SKN7 gene and containing a temperature-sensitive mutation in Hsf1 is hypersensitive to oxidative stress. Our data suggest that Skn7 and Hsf1 cooperate to achieve maximal induction of heat shock genes in response specifically to oxidative stress. We further show that, like Hsf1, Skn7 can interact with itself and is localized to the nucleus under normal growth conditions as well as during oxidative stress

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

Stability of penicillinase plasmids in staphylococcus aureus

The stability of the penicillinase plasmids of Staphylococcus aureus has been investigated both by the effects of various agents on the elimination of the plasmids and by the characterisation of mutations influencing the stability. Growth or plasmid-carrying strains in the presence of ethidium bromide enhanced the spontaneous rate of loss of plasmids in all seven strains of S.aureus tested. In one of these strains, growth in media containing acridine orange had a similar effect on plasmid loss. One of the strains grew in the presence of high concentrations of ethidium bromide. This resistance to ethidium bromide is determined by a gene located on the penicillinase plasmid and appears to be due, at least in part, to a permeability effect. Two types of mutant affected in the stability of the penicillinase plasmids have been isolated from S.aureus PS80 after treatment with ethyl methane sulphonate. In one, the mutation is present on the penicillinase plasmid and results in an inability to replicate at 42andnbsp;C; replication at 30andnbsp;C being unaffected. The second type of mutation is not located on the plasmid and causes instability of penicillinase plasmids of both compatibility groups but does not affect a plasmid conferring resistance to tetracycline. Reversion of the temperature-sensitive plasmid to temperature stability has been studied. Evidence is presented to show that this reversion is the result of integration of the plasmid into another replicon, probably the bacterial chromosome. Deletions encompassing a particular region or the plasmid reduce the frequency of this reversion. It is suggested that this region includes a gene specifying a protein involved in the integration process. A penicillinase plasmid that has a gene conferring resistance to erythromycin (ero) has been used to integrate a fragment of this plasmid into the chromosome of S.aureus PS80. The fragment includes only the ero gene of the known plasmid genes. After transduction into this constructed strain, the temperature-sensitive plasmid integrated at a considerably increased rate. Such an integration can be effected at sites distant from the ero. since linkage between the integrated plasmid and the chromosomal ero is not obligatory. It is suggested that the effect is due to the fragment including,in addition to the ero gene, a gene int that produces a protein involved in recombination between a specific site on the plasmid and sites on the chromosome. An integrated plasmid can be excised by a superinfecting plasmid. This excision is apparently independent of any recombination between the integrated and superinfecting plasmid. A gene xis that specifies a protein responsible for this excision is proposed, xis activity functions independently or int product. Deletion mapping involving irradiation of transducing phage normally gives the same linear sequence of plasmid genes. This implies that the circular DNA in a host is ruptured at a specific site. Deletion mapping of a plasmid without this putative site results in an altered linear sequence. It is proposed that this site be called end. The location on the plasmid of the genes specifying these functions is discussed and a tentative plasmid map presented. In view of the similarities between the integration and excision functions specified by the penicillinase plasmid and those specified by temperate phage, such as lambda, it is proposed that temperate phages are the precursors of staphylococcal penicillinase plasmids. It has proved impossible to remove all plasmid-like DNA from a penicillinase plasmid negative S.aureus PS80. Nevertheless there is some indication that the temperature-sensitive plasmid DNA can be separated from other plasmid-like DNA by centrifugation in neutral sucrose gradients.</p