Dual lipid modification of the yeast ggamma subunit Ste18p determines membrane localization of Gbetagamma

The pheromone response in the yeast Saccharomyces cerevisiae is mediated by a heterotrimeric G protein. The Gbetagamma subunit (a complex of Ste4p and Ste18p) is associated with both internal and plasma membranes, and a portion is not stably associated with either membrane fraction. Like Ras, Ste18p contains a farnesyl-directing CaaX box motif (C-terminal residues 107 to 110) and a cysteine residue (Cys 106) that is a potential site for palmitoylation. Mutant Ste18p containing serine at position 106 (mutation ste18-C106S) migrated more rapidly than wild-type Ste18p during sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The electrophoretic mobility of wild-type Ste18p (but not the mutant Ste18p) was sensitive to hydroxylamine treatment, consistent with palmitoyl modification at Cys 106. Furthermore, immunoprecipitation of the Gbetagamma complex from cells cultured in the presence of [(3)H]palmitic acid resulted in two radioactive species on nonreducing SDS-PAGE gels, with molecular weights corresponding to Ggamma and Gbetagamma. Substitution of serine for either Cys 107 or Cys 106 resulted in the failure of Gbetagamma to associate with membranes. The Cys 107 substitution also resulted in reduced steady-state accumulation of Ste18p, suggesting that the stability of Ste18p requires modification at Cys 107. All of the mutant forms of Ste18p formed complexes with Ste4p, as assessed by coimmunoprecipitation. We conclude that tight membrane attachment of the wild-type Gbetagamma depends on palmitoylation at Cys 106 and prenylation at Cys 107 of Ste18p

The Ethics Of Managing Short-Term Earnings: Business Managers And Business Students Rate Earnings Management Practices Implications For Academia

In 1990, Bruns and Merchant surveyed the readership of the Harvard Business Review (HBR).  Their survey asked HBR readers to rate the acceptability of earnings management practices. Prior to that study, researchers and accounting practitioners paid little attention to the morality of short-term earnings management.  However, in the wake of highly publicized financial frauds and failures, the profession and academic journals have emphasized the importance of the concepts of earnings quality and earnings management.The Bruns and Merchant survey provided 13 earnings management situations and asked the HBR readers to rate the acceptability of those practices.  In this study, we surveyed students and business managers to measure their perceptions about the morality of specific earnings management actions to determine if their perceptions are different from those of the HBR readers 15 years ago.  This article also compares the results of our study with several other studies that used the Bruns & Merchant instrument during the most recent 15 years.    Based on our findings, we discuss implications for academia

A Review Of Going Concern Prediction Studies: 1976 To Present

In 1962, the Securities and Exchange Commission (SEC) was the first to address going concern issues with Accounting Series Release (ASR) No. 90.   Then, in 1963, the AICPA issued Statement on Auditing Procedures (SAP) No. 33, in response to ASR No. 90.  Both ASR No. 90 and SAP No. 33 addressed qualifications for issues that were unresolved and the results of which were indeterminable at the statement date. Soon after the issuance of Statement on Auditing Standards (SAS) No. 2 in 1974, researchers began to conduct studies on going concern issues.  This paper provides a comprehensive review of the literature on going concern studies and updates studies by Mutchler (1983) and Asare (1990) which provide detailed reviews of the evolution of the going concern report and requirements of the standards related to auditors' assessment of going concern.  Since SAS No. 2, the profession has not provided additional guidance on going concern.  Even the Sarbanes-Oxley Act of 2002 (SOX), makes no modifications to the requirements for considering going concern and the Public Company Accounting Oversight Board has not issued guidance addressing going concern. Starting with the first going concern prediction study [McKee, 1976], this paper identifies 27 models developed for predicting the going concern opinion and identifies the primary methods used for model development; multivariate discriminant analysis (MDA), logit analysis, probit analysis, and neural networks are.  This paper also identifies; the most popular type of focused model and identifies three non-U.S. firm models, the number of factors considered in any one study,  and the predictive abilities of the models. The paper also provides an annotated bibliography for the 27 models

Astrophysical Neutrino Event Rates and Sensitivity for Neutrino Telescopes

Spectacular processes in astrophysical sites produce high-energy cosmic rays which are further accelerated by Fermi-shocks into a power-law spectrum. These, in passing through radiation fields and matter, produce neutrinos. Neutrino telescopes are designed with large detection volumes to observe such astrophysical sources. A large volume is necessary because the fluxes and cross-sections are small. We estimate various telescopes' sensitivities and expected event rates from astrophysical sources of high-energy neutrinos. We find that an ideal detector of km^2 incident area can be sensitive to a flux of neutrinos integrated over energy from 10^5 and 10^{7} GeV as low as 1.3 * 10^(-8) * E^(-2) (GeV/cm^2 s sr) which is three times smaller than the Waxman-Bachall conservative upper limit on potential neutrino flux. A real detector will have degraded performance. Detection from known point sources is possible but unlikely unless there is prior knowledge of the source location and neutrino arrival time.Comment: Section added +modification

Li Ion Conducting Polymer Based On Polyvinylidene Fluoride And Li Triflate

Li ION CONDUCTING POLYMER BASED ON POLYVINYLIDENE FLUORIDE AND Li TRIFLATE. A Series of polymer electrolyte based on Polyvinylidene Fluoride (PVDF) for solid state rechargeable lithium battery has been prepared by solution casting technique. Lithium triflate salt was used as filler with various compositions. Bulk nature and surface morphology of the polymer electrolytes were studied by X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM), respectively. The thermal properties of polymer and salt were confirmed by Differential Scanning Calorimeter (DSC). The electrical properties of electrolyte polymer membrane were studied by using impedance spectrometer. It was found that the highest ionic conductivity was obtained for PVDF + Li Triflate 10%(w/w) which is 4.5411 x 10-3 S/cm. It was also found that there was peak of each composition in the loss tangent suggests the presence of relaxing dipoles in the polymer electrolyte films. The peak shifts towards higher frequency side suggesting the speed up of the relaxation time

Pembuatan Bahan Polimer Elektrolit Padat Berbasis Nanokomposit Kitosan Montmorillonite Untuk Aplikasi Baterai

Telah dilakukan pembuatan bahan polimer elektrolit padat berbasis nanokomposit kitosan montmorillonite yang diaplikasikan dalam sistem baterai. Penelitian ini dilakukan dengan tujuan untuk menentukan komposisi optimal antara kitosan, montmorillonite dan LiClO4 sehingga diperoleh membran dengan karakteristik yang paling baik. Teknik pembuatan membran dilakukan menggunakan metode casting. Terdapat dua seri sampel yang akan di uji, yaitu membran dengan variasi komposisi montmorillonite dan variasi komposisi LiClO4. Komposisi kitosan dan montmorillonite yang digunakan pada sampel seri kedua diperoleh dari komposisi optimal membran kitosan-montmorillonite pada sampel seri pertama. Karakterisasi yang dilakukan meliputi uji tarik, pengukuran konduktivitas ionik dan identifikasi menggunakan difraksi sinar X. Penambahan montmorillonite meningkatkan kuat tarik membran dan konduktivitas ionik setelah ditambah LiClO4. Pada kondisi optimal diperoleh konduktivitas ionik 2,383 x 10-5 S/cm dan kuat tarik 15,19 Mpa pada komposisi montmorillonit 5% b/b dan LiClO4 40%. Hasil analisis difraksi sinar X menunjukkan terjadi proses interkalasi polimer kitosan ke dalam montmorillonite

Differences in transcription between free-living and CO_2-activated third-stage larvae of Haemonchus contortus

Background: The disease caused by Haemonchus contortus, a blood-feeding nematode of small ruminants, is of major economic importance worldwide. The infective third-stage larva (L3) of this gastric nematode is enclosed in a cuticle (sheath) and, once ingested with herbage by the host, undergoes an exsheathment process that marks the transition from the free-living (L3) to the parasitic (xL3) stage. This study explored changes in gene transcription associated with this transition and predicted, based on comparative analysis, functional roles for key transcripts in the metabolic pathways linked to larval development. Results: Totals of 101,305 (L3) and 105,553 (xL3) expressed sequence tags (ESTs) were determined using 454 sequencing technology, and then assembled and annotated; the most abundant transcripts encoded transthyretin-like, calcium-binding EF-hand, NAD(P)-binding and nucleotide-binding proteins as well as homologues of Ancylostoma-secreted proteins (ASPs). Using an in silico-subtractive analysis, 560 and 685 sequences were shown to be uniquely represented in the L3 and xL3 stages, respectively; the transcripts encoded ribosomal proteins, collagens and elongation factors (in L3), and mainly peptidases and other enzymes of amino acid catabolism (in xL3). Caenorhabditis elegans orthologues of transcripts that were uniquely transcribed in each L3 and xL3 were predicted to interact with a total of 535 other genes, all of which were involved in embryonic development. Conclusion: The present study indicated that some key transcriptional alterations taking place during the transition from the L3 to the xL3 stage of H. contortus involve genes predicted to be linked to the development of neuronal tissue (L3 and xL3), formation of the cuticle (L3) and digestion of host haemoglobin (xL3). Future efforts using next-generation sequencing and bioinformatic technologies should provide the efficiency and depth of coverage required for the determination of the complete transcriptomes of different developmental stages and/or tissues of H. contortus as well as the genome of this important parasitic nematode. Such advances should lead to a significantly improved understanding of the molecular biology of H. contortus and, from an applied perspective, to novel methods of intervention

Law Students and Cell Phone Use: Results of a Six-School Survey

The sight of a law student using his or her cell phone now is so common that law professors do not give it a second thought. But what, exactly, is the student doing? Texting with friends? Shopping? Watching a movie? To try to find out, during the Fall 2019 semester we asked our six diverse law schools to take an online survey consisting of eighteen questions. To our knowledge, this is the first phone survey of law students. This paper presents the results of the survey, exploring applications used (text, social media, email, etc.) and differences by audience (e.g., whether students used text or email with employers as opposed to friends)

Induction of antibody-mediated neutralization in SIVmac239 by a naturally acquired V3 mutation

AbstractAchieving humoral immunity against human immunodeficiency virus (HIV) is a major obstacle in AIDS vaccine development. Despite eliciting robust humoral responses to HIV, exposed hosts rarely produce broadly neutralizing antibodies. The present study utilizes simian immunodeficiency virus (SIV) to identify viral epitopes that conferred antibody neutralization to clone SIV/17E-CL, an in vivo variant derived from neutralization resistant SIVmac239. Neutralization assays using rhesus macaque monoclonal antibodies were performed on viruses engineered to express single or multiple amino acid mutations. Results identified a single amino acid mutation, P334R, in the carboxy-terminal half of the V3 loop as a critical residue that induced neutralization while retaining normal glycoprotein expression on the surface of the virus. Furthermore, the R334 residue yielded neutralization sensitivity by antibodies recognizing diverse conformational and linear epitopes of gp120, suggesting that neutralization phenotype was a consequence of global structural changes of the envelope protein rather than a specific site epitope