Targeted Mutagenesis of the Oligopeptide Repeat Domain of the Yeast Prion Sup35

The formation of prions in the baker’s yeast Saccharomyces cerevisiae is determined by amino acid composition rather than the primary sequence of amino acids. The infectious amyloid proteins known as prions undergo nucleation and propagation, two distinct activities critical for prion formation. The ability for prions to be transferred from cell to cell, or propagate, is of interest not only in yeast prions but also in prion diseases such as the mammalian spongiform encephalopathies. Prion formation has been widely studied in yeast prions, however, the fundamental mechanisms behind the specific process of propagation of prions from cell to cell are not yet understood. In the most well-studied yeast prion, the prion form [PSI+] of Sup35, a domain of 5 ½ degenerate oligopeptide repeats called the oligopeptide repeat domain (ORD) has been shown to be important for prion propagation and to have a distinct amino acid composition as compared to the nucleation domain region. A library mutagenesis experiment has identified amino acids that favor or disfavor prion propagation in yeast cells. To confirm the results of the random library mutagenesis experiment, we generated several clones in which a portion of the ORD (the fourth oligopeptide repeat) was replaced with defined sequences expected to propagate or fail to propagate

Frio brine sequestration pilot in the Texas Gulf Coast

A field experiment to pioneer CO2 injection for sequestration in a brine-bearing sandstone-shale sequence in the Texas Gulf Coast, USA, is in the preinjection modeling and planning phase. Innovations in this experiment include (1) CO2 injection into high-volume highpermeability rocks that have storage capacity sufficient to impact greenhouse gas emissions, (2) injection into a setting lacking the complications introduced by hydrocarbons and perturbations resulting from production and secondary recovery, and (3) intensive pre-, syn-, and post-injection monitoring and modeling for validation of the effectiveness of sequestration. The experiment is designed to provide a rapid increase in information from a small-volume and short-duration injection.Bureau of Economic Geolog

Description of the computations and pilot procedures for planning fuel-conservative descents with a small programmable calculator

A simplified flight management descent algorithm was developed and programmed on a small programmable calculator. It was designed to aid the pilot in planning and executing a fuel conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The algorithm may also be used for planning fuel conservative descents when time is not a consideration. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard temperature effects. The flight management descent algorithm and the vertical performance modeling required for the DC-10 airplane is described

A comparison of two commercial and the terminal configured vehicle area navigation systems

A comparison was made of some of the more important features of two commercially available area navigation systems and the Terminal Configured Vehicle (TCV) area navigation system. Topics discussed included system design criteria, system elements, calculation of the navigation solution, and presentation of guidance information

Heavy mineral stratigraphy of the Unayzah Formation and Basal Khuff Clastics (Carboniferous to Permian) of Central Saudi Arabia

A study of heavy mineral assemblages in the Unayzah Reservoir sandstones of central Saudi Arabia has identified successive changes in provenance signature. These define four heavy mineral units that are of regional extent and largely coincident with the four main depositional units defined by previous authors: Unayzah C, Unayzah B, Unayzah A and the Basal Khuff Clastics. Sandstone bodies with anomalous mineral signatures also occur, however, especially within the Unayzah B Member. These are attributed to local supply of sand from pre-Unayzah Paleozoic sandstones exposed on the Central Arabian Arch and on intrabasinal highs. The stratigraphic changes in mineralogy reflect successive developments in the geography and climate of the region and in the pattern of sand sourcing and transport. The Unayzah C sands and the majority of Unayzah B sands were derived from the south but whereas the southerly derived Unayzah C sands appear to have been derived from pre-existing mature sandstones, those of Unayzah B were sourced from a wider range of rock types including crystalline basement. This contrast is interpreted as indicating that a significant hiatus may separate the two units. The Unayzah B sands are also characterised by the common presence of apatite, indicating that the source rocks were relatively unweathered. This observation is compatible with the glacial origin attributed to many of the Unayzah B sediments. A further change in provenance signature takes place at the base the newly recognised ‘un-named middle Unayzah member’, equivalent to the base of Unayzah A of previous authors. This is associated with the onset of red-bed sedimentation throughout the area. Unayzah A sedimentation was terminated by a fall in sea level that led to the formation of a widespread unconformity and to the development of deeply incised valleys along the western basin margin. In most of the study area this unconformity corresponds to the base of the Khuff Formation, but in the east of the area, where the succession is more complete, it is believed to occur within the Unayzah Formation, at a level equivalent to the base of the Upper Gharif Member of Oman. By identifying lateral and vertical changes in sand provenance, heavy mineral analysis provides an important additional tool in the stratigraphic analysis of the Permian sandstone succession of Saudi Arabia, both at the regional scale and wand at the scale of individual reservoir sandstone successions

Traffic Flow: An Approach towards Modeling the Right Lane Rule

We attempted to model and analyze the effect of the right hand rule for the 2014 COMAP Math Modeling Competition. In order to analyze the right hand rule we started with Greenshield’s macroscopic approach and modified it to simulate the effects of the right hand rule. By analyzing the resulting changes in the flow and density of the system we determined the performance of the rule in varying traffic densities. Next we looked at the performance by modeling traffic flow when the rule is strictly adhered to, as compared to an intermediate, where the rule is followed until the critical density is reached. In the intermediate model we show how traffic flow can be maximized if people no longer follow the right hand rule after the critical density

Facebook surveillance of former romantic partners: Associations with post-breakup recovery and personal growth

Copyright @ 2012 Mary Ann Liebert, Inc.This article has been made available through the Brunel Open Access Publishing Fund.Previous research has found that continuing offline contact with an ex-romantic partner following a breakup may disrupt emotional recovery. The present study examined whether continuing online contact with an ex-partner through remaining Facebook friends and/or engaging in surveillance of the ex-partner's Facebook page inhibited postbreakup adjustment and growth above and beyond offline contact. Analysis of the data provided by 464 participants revealed that Facebook surveillance was associated with greater current distress over the breakup, more negative feelings, sexual desire, and longing for the ex-partner, and lower personal growth. Participants who remained Facebook friends with the ex-partner, relative to those who did not remain Facebook friends, reported less negative feelings, sexual desire, and longing for the former partner, but lower personal growth. All of these results emerged after controlling for offline contact, personality traits, and characteristics of the former relationship and breakup that tend to predict postbreakup adjustment. Overall, these findings suggest that exposure to an ex-partner through Facebook may obstruct the process of healing and moving on from a past relationship

Planning fuel-conservative descents in an airline environmental using a small programmable calculator: Algorithm development and flight test results

A simple, airborne, flight-management descent algorithm was developed and programmed into a small programmable calculator. The algorithm may be operated in either a time mode or speed mode. The time mode was designed to aid the pilot in planning and executing a fuel-conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The speed model was designed for planning fuel-conservative descents when time is not a consideration. The descent path for both modes was calculated for a constant with considerations given for the descent Mach/airspeed schedule, gross weight, wind, wind gradient, and nonstandard temperature effects. Flight tests, using the algorithm on the programmable calculator, showed that the open-loop guidance could be useful to airline flight crews for planning and executing fuel-conservative descents

Mapping the Beta-Sheet Structure of the Yeast Prion Sup35 through Creation of Targeted Mutant Forms

Proteins with an aggregated form rich in beta-sheet structure are known as amyloids, of which a subset are infectious. These infectious proteins are known as prions and cause diseases including bovine spongiform encephalopathy (“Mad Cow” disease). Several prions have been identified in the baker’s yeast, Saccharomyces cerevisiae. One of the most well-studied yeast prions is the protein Sup35. To understand the fine protein structure of Sup35 better, we used PCR-based mutagenesis to introduce a lysine residue (a charged amino acid) at five defined places in the protein sequence of Sup35. We describe our process for creating these mutant versions and the results of DNA sequencing of each mutant version. The next step will be to assess prion formation and stability of clones with the correct sequences. Understanding the behavior of yeast prions has proven helpful in understanding human amyloid diseases and further studies on these yeast prions, including Sup35, will expand our knowledge further