Anchoring of Surface Proteins to the Cell Wall of Staphylococcus aureus. III. Lipid II is an in vivo peptidoglycan substrate for sortase-catalyzed surface protein anchoring

Surface proteins of Staphylococcus aureus are anchored to the cell wall peptidoglycan by a mechanism requiring a C-terminal sorting signal with an LPXTG motif. Surface proteins are first synthesized in the bacterial cytoplasm and then transported across the cytoplasmic membrane. Cleavage of the N-terminal signal peptide of the cytoplasmic surface protein P1 precursor generates the extracellular P2 species, which is the substrate for the cell wall anchoring reaction. Sortase, a membrane-anchored transpeptidase, cleaves P2 between the threonine (T) and the glycine (G) of the LPXTG motif and catalyzes the formation of an amide bond between the carboxyl group of threonine and the amino group of cell wall cross-bridges. We have used metabolic labeling of staphylococcal cultures with [32P]phosphoric acid to reveal a P3 intermediate. The 32P-label of immunoprecipitated surface protein is removed by treatment with lysostaphin, a glycyl-glycine endopeptidase that separates the cell wall anchor structure. Furthermore, the appearance of P3 is prevented in the absence of sortase or by the inhibition of cell wall synthesis. 32P-Labeled cell wall anchor species bind to nisin, an antibiotic that is known to form a complex with lipid II. Thus, it appears that the P3 intermediate represents surface protein linked to the lipid II peptidoglycan precursor. The data support a model whereby lipid II-linked polypeptides are incorporated into the growing peptidoglycan via the transpeptidation and transglycosylation reactions of cell wall synthesis, generating mature cell wall-linked surface protein

Theory of Polaron Resonance in Quantum Dots and Quantum-Dot Molecules

The theory of exciton coupling to photons and LO phonons in quantum dots (QDs) and quantum-dot molecules (QDMs) is presented. Resonant-round trips of the exciton between the ground (bright) and excited (dark or bright) states mediated by the LO-phonon alter the decay time and yield the Rabi oscillation. The initial distributions of the population in the ground and the excited states dominate the oscillating amplitude and frequency. This property provides a detectable signature to the information stored in a qubit made from QD or QDM for a wide range of temperature T. Our results presented herein provide an explanation to the anomaly on T-dependent decay in self-assembled InGaAs/GaAs QDMs recently reported by experiment.Comment: 30 pages, 8 figure

Education of the Professional Accountant: An Empirical Study

This paper (1) reviews the literature related to the educational needs of the professional accountant, including several major studies done in the United States, and the accreditation standards of the American Assembly of Collegiate Schools of Business (A.A.C.S.B.) and (2) investigates empirically the perceptions of Canadian accounting educators and practitioners of the educational needs of professional accountants to determine the extent to which these needs are being fulfilled by the current university undergraduate programs in Canada. The literature review confirms the theme that accountants should be broadly educated as well as being technically competent. A calendar review of eleven major Canadian universities provides an indication of the current structure of undergraduate accounting programs in Canada. An opinion survey of educators and practitioners suggests a rather different structure. Among other results, respondents of the survey suggested a higher percentage of general education be included in undergraduate accounting programs especially for certain Ontario and Quebec universities. A greater emphasis should be placed on English language and composition than currently prevails in many major universities. It is hoped that the analysis will prove useful to those involved in curriculum design at the baccalaureate level.L'auteur (1) passe en revue différents ouvrages relatifs à la formation requise pour les comptables professionnels, notamment quelques études importantes réalisées aux États-Unis ainsi que les normes d'admission de /' "American Assembly of Collegiate Schools of Business" (A.A.C.S.B.) et (2) étudie empirique-ment la façon dont les professeurs de comptabilité et les comptables canadiens conçoivent la formation requise pour l'exercice de la profession, dans le but de comparer leurs opinions aux différents programmes de premier cycle actuellement en vigueur au Canada. La recension des écrits révèle que les futurs comptables doivent recevoir une solide formation générale tout autant qu'une formation à leur domaine de spécialité. Une analyse des annuaires de neuf grandes universités canadiennes montre la structure actuelle des programmes de premier cycle , du reste contredite par un sondage d'opinions mené auprès d'enseignants et de praticiens. Les enquêtés, en effet, ont notamment proposé d'intensifier la formation générale dans les programmes de comptabilité de premier cycle, en particulier dans certaines universités ontariennes et québécoises; ils recommandent de mettre davantage l'accent sur la langue, la composition et la littérature anglaises. Cette étude devrait se révéler utile pour les spécialistes chargés d'élaborer les programmes de baccalauréat

Investigating 1d and 1d/1d Modeling Using SWMM

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

Rank 3 permutation characters and maximal subgroups

In this paper we classify all maximal subgroups M of a nearly simple primitive rank 3 group G of type L=Omega_{2m+1}(3), m > 3; acting on an L-orbit E of non-singular points of the natural module for L such that 1_P^G <=1_M^G where P is a stabilizer of a point in E. This result has an application to the study of minimal genera of algebraic curves which admit group actions.Comment: 41 pages, to appear in Forum Mathematicu

Automatic Fall Risk Detection based on Imbalanced Data

In recent years, the declining birthrate and aging population have gradually brought countries into an ageing society. Regarding accidents that occur amongst the elderly, falls are an essential problem that quickly causes indirect physical loss. In this paper, we propose a pose estimation-based fall detection algorithm to detect fall risks. We use body ratio, acceleration and deflection as key features instead of using the body keypoints coordinates. Since fall data is rare in real-world situations, we train and evaluate our approach in a highly imbalanced data setting. We assess not only different imbalanced data handling methods but also different machine learning algorithms. After oversampling on our training data, the K-Nearest Neighbors (KNN) algorithm achieves the best performance. The F1 scores for three different classes, Normal, Fall, and Lying, are 1.00, 0.85 and 0.96, which is comparable to previous research. The experiment shows that our approach is more interpretable with the key feature from skeleton information. Moreover, it can apply in multi-people scenarios and has robustness on medium occlusion

Clinical markers of Crohn\u27s disease severity and their association with opiate use

BACKGROUND: The safety of opiate use for patients with Crohn\u27s disease (CD) has long been a concern. The recent Crohn\u27s therapy, resource, evaluation, and assessment tool (TREAT) registry update has added to these concerns by demonstrating an association of opiate use with an increased risk of infection and death in CD. While the association is clear, the relationship of opiates to these negative outcomes is not. It is unknown whether opiates are a contributing factor to these negative outcomes or if their use is merely a marker of more severe disease. We hypothesized that opiate use is not harmful in CD but is a marker of disease severity and would be associated with commonly accepted clinical markers of severe CD such as early age at CD onset, disease duration, small intestinal involvement, a history of fistula or stricture, and lower quality of life (QOL) scores. METHODS: Data on CD history including pain medication usage were obtained from an interviewer directed survey of patients admitted to two tertiary care hospitals over a 2-year period. CD as the primary admitting diagnosis was not required. Active opiate use was defined by usage within the past month prior to admission. RESULTS: A total of 133 patients were approached to participate, of whom 108 consented to the survey, and 51 were active opiate users. Opiate using CD patients were more commonly smokers (22% vs. 3.45%, P \u3c 0.010), had fistulas (40% vs. 22.4%, P \u3c 0.048) and had a poorer quality of life score by short form inflammatory bowel disease questionnaire (mean 3.80 vs. 4.34, P \u3c 0.036) than non-opiate users. No difference was found between opiate users and non-users for age of diagnosis, disease duration, or a history of strictures. CONCLUSIONS: The study findings demonstrate that opiate use in CD is associated with markers of disease severity including fistulas, smoking, and lower QOL scores. The findings suggest that opiates may not be directly harmful to patients with CD, but may merely be another marker of disease severity. However, given opiates unproven benefits for long term CD pain control and risk of dependence, caution should still be exercised in their use

On Neutrino Masses and Family Replication

The old issue of why there are more than one family of quarks and leptons is reinvestigated with an eye towards the use of anomaly as a tool for constraining the number of families. It is found that, by assuming the existence of right-handed neutrinos (which would imply that neutrinos will have a mass) and a new chiral SU(2) gauge theory, strong constraints on the number of families can be obtained. In addition, a model, based on that extra SU(2), is constructed where it is natural to have one "very heavy" fourth neutrino and three almost degenerate light neutrinos whose masses are all of the Dirac type.Comment: RevTex, 12 pages with 1 figure, minor changes to the text and added acknowledgment