3,045 research outputs found
Recommended from our members
Modulation of sterol homeostasis by the Cdc42p effectors Cla4p and Ste20p in the yeast Saccharomyces cerevisiae
This article is available open access through the publisherâs website at the link below. Copyright @ 2009 The Authors.The conserved Rho-type GTPase Cdc42p is a key regulator of signal transduction and polarity in eukaryotic cells. In the yeast Saccharomyces cerevisiae, Cdc42p promotes polarized growth through the p21-activated kinases Ste20p and Cla4p. Previously, we demonstrated that Ste20p forms a complex with Erg4p, Cbr1p and Ncp1p, which all catalyze important steps in sterol biosynthesis. CLA4 interacts genetically with ERG4 and NCP1. Furthermore, Erg4p, Ncp1p and Cbr1p play important roles in cell polarization during vegetative growth, mating and filamentation. As Ste20p and Cla4p are involved in these processes it seems likely that sterol biosynthetic enzymes and p21-activated kinases act in related pathways. Here, we demonstrate that the deletion of either STE20 or CLA4 results in increased levels of sterols. In addition, higher concentrations of steryl esters, the storage form of sterols, were observed in cla4Î cells. CLA4 expression from a multicopy plasmid reduces enzyme activity of Are2p, the major steryl ester synthase, under aerobic conditions. Altogether, our data suggest that Ste20p and Cla4p may function as negative modulators of sterol biosynthesis. Moreover, Cla4p has a negative effect on steryl ester formation. As sterol homeostasis is crucial for cell polarization, Ste20p and Cla4p may regulate cell polarity in part through the modulation of sterol homeostasis.Deutsche Forschungsgemeinschaft and the Austrian FWF
Proceedings of the IEA-workshop on intense neutron sources Karlsruhe, Germany, 21-23 September 1992. IEA-implementing agreement for a programme of research and development on fusion materials. Working group task - annex II
Sensitivity to the KARMEN Timing Anomaly at MiniBooNE
We present sensitivities for the MiniBooNE experiment to a rare exotic pion
decay producing a massive particle, Q^0. This type of decay represents one
possible explanation for the timing anomaly reported by the KARMEN
collaboration. MiniBooNE will be able to explore an area of the KARMEN signal
that has not yet been investigated
Searching for Sakitawak: Place and People in Northern Saskatchewan\u27s Ăle-Ă -la-Crosse
This presentation is a history of a small community, Ăle-Ă -la-Crosse, located in an area now part of Saskatchewan, Canada. With an historic reputation for cooperation and enviable trading circumstances, its residents traditionally have determined that protection of the community ensured the best opportunities for the advancement and security of individuals. As a result of this belief, residents reinforced their own understandings of sustainability as a means to ensure personal success. The communityâs fame for hosting such a set of norms grew, particularly from the eighteenth to the twentieth century, and outsiders often visited to improve their own efforts as a result of this reputation. Given the belief that community longevity assured individual concerns, many visitors quickly decided to adopt local processes even if those functions contrasted sharply from their own original beliefs. Based on these decisions, the visitorsâ institutions experienced changes as well.
Through this social cooperation to better ensure personal success, a culture began to develop, and so the villageâs distinctive administrative and economic processes were continued through family and neighbourly ties. Some characteristics, such as multiculturalism, shared land use, complex trading activities, and sustainability, further distinguished Ăle-Ă -la-Crosse as a result. Though well aware of the village a number of parties (such as the Hudsonâs Bay Company and the Canadian government), still regularly excluded the community from their deliberations because of its unique ability to supposedly need less intervention considered necessary elsewhere. These various corporate and political authorities, concerned with their own existence, instead emphasised the conditions of communities that demonstrated social hostility, monetary difficulties, and other forms of disparity. As these historic parties failing to appreciate the villageâs positive components in their fullest form, historians also did not integrate the village into their narratives since they almost always focused on conflict and change in their investigations. Because of this missing analysis about Ăle-Ă -la-Crosse, historical accounts have created lacunae in our understanding and awareness not just of local but also of provincial and national issues pertaining to âdevelopment.â Today, the lack of historic and historical awareness has as well directly impacted a modern day Indigenous âland claimâ. Particularly when examining âabsenceâ and âoverlapâ in a spaceâs natural and social form, Ăle-Ă -la-Crosseâs story from its earliest existence to its present shape can finally remind us how local conditions âeven before humans started living in those circumstances â can teach us about how to survive and succeed today as individuals and as part of a larger community and country. It also reminds us how we should pay more attention to peace, cooperation and interaction in both intellectual and social circles
The Heavy-Flavour Contribution to Proton Structure
We present theoretical and experimental considerations pertaining to deeply
inelastic heavy-flavour production at HERA. The various theoretical
uncertainties in the cross section calculation are discussed. Cuts are imposed
to determine the fraction of charm production accessible to the detectors. The
production of charm at asymptotic and bottom production are also covered.
Experimental aspects include current charm production data analysis and
prospects for future analyses including anticipated high precision and
distinguishing photon-gluon fusion charm events from excitation from the charm
parton density. The feasibility of measuring is
investigated.Comment: 22 total pages with 16 figures. To appear in abbreviated form in the
proceedings of the workshop ``Future Physics at HERA'', DESY, Hamburg, 199
Search for Exotic Muon Decays
Recently, it has been proposed that the observed anomaly in the time
distribution of neutrino induced reactions, reported by the KARMEN
collaboration, can be interpreted as a signal from an exotic muon decay branch
mu+ to e+ X. It has been shown that this hypothesis gives an acceptable fit to
the KARMEN data if the boson X has a mass of m_X=103.9MeV/c^2, close to the
kinematical limit. We have performed a search for the X particle by studying
for the first time the very low energy part of the Michel spectrum in mu+
decays. Using a HPGe detector setup at the muE4 beamline at PSI we find
branching ratios BR(mu+ to e+ X)<5.7e-4 (90% C.L.) for most of the region
103MeV/c^2<m_X<105MeV/c^2.Comment: 9 page
The reaction from threshold up to 570 MeV
The reaction has been studied in a
kinematically complete measurement with a large acceptance time-of-flight
spectrometer for incident neutron energies between threshold and 570 MeV. The
proton-proton invariant mass distributions show a strong enhancement due to the
pp() final state interaction. A large anisotropy was found in the
pion angular distributions in contrast to the reaction . At small energies, a large forward/backward asymmetry has been
observed. From the measured integrated cross section , the isoscalar cross section has been extracted.
Its energy dependence indicates that mainly partial waves with Sp final states
contribute. Note: Due to a coding error, the differential cross sections as shown in Fig. 9 are too small by a factor of two, and
inn Table 3 the differential cross sections
are too large by a factor of . The integrated cross sections and all
conclusions remain unchanged. A corresponding erratum has been submitted and
accepted by European Physics Journal.Comment: 18 pages, 16 figure
- âŠ