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Abstract The Escherichia coli RbsB ribose binding protein has been used as a scaffold for predicting new ligand binding functions through in silico modeling, yet with limited success and reproducibility. In order to possibly improve the success of predictive modeling on RbsB, we study here the influence of individual residues on RbsB-mediated signaling in a near complete library of alanine-substituted RbsB mutants. Among a total of 232 tested mutants, we found 10 which no longer activated GFPmut2 reporter expression in E. coli from a ribose-RbsB hybrid receptor signaling chain, and 13 with significantly lower GFPmut2 induction than wild-type. Quantitative mass spectrometry abundance measurements of 25 mutants and wild-type RbsB in periplasmic space showed four categories of effects. Some (such as D89A) seem correctly produced and translocated but fail to be induced with ribose. Others (such as N190A) show lower induction probably as a result of less efficient production, folding and translocation. The third (such as N41A or K29A) have defects in both induction and abundance. The fourth category consists of semi-constitutive mutants with increased periplasmic abundance but maintenance of ribose induction. Our data show how RbsB modeling should include ligand-binding as well as folding, translocation and receptor binding.

Large oil spills have negative effects on marine ecosystems, but the effects of chronic smallscale spills are less well understood. Here, Brussaard et al. detect high bioavailability and toxicity of small-scale crude oil spills within 24 hours after release, which are associated with localised declines in marine plankton.

Different studies have shown circadian variation of ischemic burden among patients with ST-Elevation Myocardial Infarction (STEMI), but with controversial results. The aim of this study was to analyze circadian variation of myocardial infarction size and in-hospital mortality in a large multicenter registry.This retrospective, registry-based study was based on data from AMIS Plus, a large multicenter Swiss registry of patients who suffered myocardial infarction between 1999 and 2013. Peak creatine kinase (CK) was used as a proxy measure for myocardial infarction size. Associations between peak CK, in-hospital mortality, and the time of day at symptom onset were modelled using polynomial-harmonic regression methods.6,223 STEMI patients were admitted to 82 acute-care hospitals in Switzerland and treated with primary angioplasty within six hours of symptom onset. Only the 24-hour harmonic was significantly associated with peak CK (p = 0.0001). The maximum average peak CK value (2,315 U/L) was for patients with symptom onset at 23:00, whereas the minimum average (2,017 U/L) was for onset at 11:00. The amplitude of variation was 298 U/L. In addition, no correlation was observed between ischemic time and circadian peak CK variation. Of the 6,223 patients, 223 (3.58%) died during index hospitalization. Remarkably, only the 24-hour harmonic was significantly associated with in-hospital mortality. The risk of death from STEMI was highest for patients with symptom onset at 00:00 and lowest for those with onset at 12:00.As a part of this first large study of STEMI patients treated with primary angioplasty in Swiss hospitals, investigations confirmed a circadian pattern to both peak CK and in-hospital mortality which were independent of total ischemic time. Accordingly, this study proposes that symptom onset time be incorporated as a prognosis factor in patients with myocardial infarction.

The present study shows that simple forms for the generation functions, if connected to appropriate electronic path (electron range), can be successfully used to describe the collection efficiency in EBIC devices. Both uniform and point-like source generation functions are considered here and for which two phenomenological electronic paths, depending on the incident beam energy, are obtained. Complexities that might arise solving the continuity equations are, thus, avoided. The calculations were performed for the Schottky diodes Au/Ge. Key words: Elecdtron beam induced current (EBIC), generation function, electron penetration, schottky diodes of Ge, INTRODUCTION The Electron Beam Induced Current (EBIC) is one of the frequently used methods in the Scanning Electron Microscopy (SEM) to investigate the electrical properties of defects in semiconductors (1). [...]

Genetically engineered bioreporters are an excellent complement to traditional methods of chemical analysis. The application of fluorescence flow cytometry to detection of bioreporter response enables rapid and efficient characterization of bacterial bioreporter population response on a single-cell basis. In the present study, intrapopulalion response variability was used to obtain higher analytical sensitivity and precision. We have analyzed flow cytometric data for an arsenic-sensitive bacterial bioreporter using an artificial neural network-based adaptive clustering approach (a single-layer perceptron model). Results for this approach are far superior to other methods that we have applied to this fluorescent bioreporter (e.g., the arsenic detection limit is 0.01 [micro]M, substantially lower than for other detection methods/ algorithms). The approach is highly efficient computationally and can be implemented on a real-time basis, thus having potential for future development of high-throughput screening applications.

Streptococcus gordonii [alpha]-phosphoglucomutase, which converts glucose 6-phosphate to glucose 1-phosphate, is encoded by pgm. The pgm transcript is monocistronic and is initiated from a [[alpha].sup.A]-like promoter. Mutants with a gene disruption in pgm exhibited an altered cell wall muropeptide pattern and a lower teichoic acid content, and had reduced fitness both in vitro and in vivo. In vitro, the reduced fitness included reduced growth, reduced viability in the stationary phase and increased autolytic activity. In vivo, the pgm-deficient strain had a lower virulence in a rat model of experimental endocarditis.

Research has been conducted on Bacillus subtilis strain W23. The sequencing of the genes which direct the teichoic acid synthesis in this strain has been carried out and the features of these genes and the participation of their products in the poly(ribitol phosphate) biosynthesis pathway are presented.

Puttini, Stefania, Ahmed T. Beggah, Antoine Ouvrard-Pascaud, Christine Legris, Marcel Blot-Chabaud, Nicolette Farman, and Frederic Jaisser. Tetracycline-inducible gene expression in cultured rat renal CD cells and in intact CD from transgenic mice. Am J Physiol Renal Physiol 281: F1164-F1172, 2001. First published August 30, 2001; 10.1152/ajprenal.00360.2000.--The renal collecting duct (CD) plays a key role in the control of ion and fluid homeostasis. Several genetic diseases that involve mutations in genes encoding for ion transporters or hormone receptors specifically expressed in CD have been described. Suitable cellular or transgenic animal models expressing such mutated genes in an inducible manner should represent attractive systems for structure-function relationship analyses and the generation of appropriate physiopathological models of related diseases. Our first goal was to develop a CD cell line that allows inducible gene expression using the tetracycline-inducible system (Tet-On). We designed several strategies aimed at the development of a tight and highly inducible system in RCCD1 cells, a rat cortical collecting duct (CCD) cell line exhibiting several properties of the native CCD. Analysis of reporter gene expression demonstrated that the Tet-On system is suitable for inducible gene expression in these cells. In a second step, we have tested whether transgenic Tet-On mice expressing the tetracycline transactivator under the control of the human cytomegalovirus promoter were suitable for inducible gene expression in tubule epithelial cells. The results indicate that, in vivo, the inducible expression of the lacZ reporter gene appeared to be restricted to the CD. This particular strain of transgenic mice may therefore be useful for the expression of genes of interest in an inducible manner in the collecting duct. transgenic; inducible systems; conditional systems; kidney; physiopathology Received 31 December 2000; accepted in final form 30 July 2001

Results show that secretion of aspartic proteinase Sap1p is dependent on a 12 amino acid residue propeptide. However, under conditions of simultaneous culture of Candida albicans carrying mutated and non-mutated propeptide, limited synthesis of the enzyme occurs suggesting that the recombinant enzyme maturation follows a combination of intra-and inter-molecular pathways.

Association of the cytoplasmic NH2 terminal of the Na,K-ATPase beta subunit with the alpha subunit is necessary for the oligomerization and formation of active Na,K-ATPase on the endoplasmic reticulum. The interaction changes the conformation of both the alpha and the beta subunits. The alpha subunit associated with the beta subunit resists cellular degradation, and gains the ability to change its conformation and hydrolyze ATP. The binding of the beta subunit to the alpha subunit increases its protease resistance.

Several G protein-coupled receptors promote the protein kinase A (PKA)-mediated phosphorylation of Na-K-adenosinetriphosphatase (Na-K-ATPase) in different cell systems. The phosphorylation inducing receptors are adrenergic, dopaminergic and muscarinic cholinergic receptor subspecies. Stimulation of the receptors induces phosphorylation of the wild-type and PKC phosphorylation site-deficient Na-K-ATPase. However, the Na-K-ATPase alpha subunit, lacking the PKA phosphorylation site, does not undergo phosphorylation.