50 research outputs found

    The structure of PghL hydrolase bound to its substrate poly-γ-glutamate

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    The identification of new strategies to fight bacterial infections in view of the spread of multiple resistance to antibiotics has become mandatory. It has been demonstrated that several bacteria develop poly-?-glutamic acid (?-PGA) capsules as a protection from external insults and/or host defence systems. Among the pathogens that shield themselves in these capsules are Bacillus\ua0anthracis, Francisella\ua0tularensis and several Staphylococcus strains. These are important pathogens with a profound influence on human health. The recently characterised ?-PGA hydrolases, which can dismantle the ?-PGA-capsules, are an attractive new direction that can offer real hope for the development of alternatives to antibiotics, particularly in cases of multidrug resistant bacteria. We have characterised in detail the cleaving mechanism and stereospecificity of the enzyme PghL (previously named YndL) from Bacillus\ua0subtilis encoded by a gene of phagic origin and dramatically efficient in degrading the long polymeric chains of ?-PGA. We used X-ray crystallography to solve the three-dimensional structures of the enzyme in its zinc-free, zinc-bound and complexed forms. The protein crystallised with a ?-PGA hexapeptide substrate and thus reveals details of the interaction which could explain the stereospecificity observed and give hints on the catalytic mechanism of this class of hydrolytic enzymes

    Effect of valsartan on angiotensin II-induced plasminogen activator inhibitor-1 biosynthesis in arterial smooth muscle cells

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    Previous studies have shown that angiotensin II stimulates the synthesis of plasminogen activator inhibitor-1 in cultured vascular cells, which suggests that activation of the renin-angiotensin system may impair fibrinolysis. We have investigated the effects of angiotensin II and of valsartan, a recently developed angiotensin II antagonist that is highly specific and selective for the angiotensin II subtype 1 receptor, on plasminogen activator inhibitor-1 secretion by smooth muscle cells isolated from rat and human vessels. Angiotensin II induced a time- and concentration-dependent increase of plasminogen activator inhibitor activity in supernatants of rat aortic cells, which reached a plateau after 6 hours of incubation with 100 nmol/L angiotensin II (2.4+/-0.6-fold over control value; P:<0.001). The angiotensin II-induced plasminogen activator inhibitor activity was inhibited, in a concentration-dependent manner, by valsartan with an IC(50) value of 21 nmol/L. Valsartan fully prevented the angiotensin II-induced increase in plasminogen activator inhibitor-1 protein and mRNA. Furthermore, angiotensin II doubled the secretion of plasminogen activator inhibitor-1 by smooth muscle cells obtained from human umbilical and internal mammary arteries, and valsartan fully prevented it. Angiotensin II did not affect the secretion of tissue plasminogen activator antigen by any of the cell systems tested. Thus, valsartan effectively inhibits angiotensin II-induced plasminogen activator inhibitor-1 secretion without affecting that of tissue plasminogen activator in arterial rat and human smooth muscle cells

    Characterization of FUS Mutations in Amyotrophic Lateral Sclerosis Using RNA-Seq

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    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease resulting in severe muscle weakness and eventual death by respiratory failure. Although little is known about its pathogenesis, mutations in fused in sarcoma/translated in liposarcoma (FUS) are causative for familial ALS. FUS is a multifunctional protein that is involved in many aspects of RNA processing. To elucidate the role of FUS in ALS, we overexpressed wild-type and two mutant forms of FUS in HEK-293T cells, as well as knocked-down FUS expression. This was followed by RNA-Seq to identify genes which displayed differential expression or altered splicing patterns. Pathway analysis revealed that overexpression of wild-type FUS regulates ribosomal genes, whereas knock-down of FUS additionally affects expression of spliceosome related genes. Furthermore, cells expressing mutant FUS displayed global transcription patterns more similar to cells overexpressing wild-type FUS than to the knock-down condition. This observation suggests that FUS mutants do not contribute to the pathogenesis of ALS through a loss-of-function. Finally, our results demonstrate that the R521G and R522G mutations display differences in their influence on transcription and splicing. Taken together, these results provide additional insights into the function of FUS and how mutations contribute to the development of ALS.ALS Foundation NetherlandsAdessium FoundationSeventh Framework Programme (European Commission) (grant number 259867)Thierry Latran FoundationNational Institutes of Health (U.S.) (NIH/NINDS grant R01NS073873)National Institute of Neurological Disorders and Stroke (U.S.) (NIH/NINDS grant numbers 1R01NS065847

    80Se(n,?) cross-section measurement at CERN n TOF

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    Radiative neutron capture cross section measurements are of fundamental importance for the study of the slow neutron capture (s-) process of nucleosynthesis. This mechanism is responsible for the formation of most elements heavier than iron in the Universe. Particularly relevant are branching nuclei along the s-process path, which are sensitive to the physical conditions of the stellar environment. One such example is the branching at 79^{79}Se (3.27 × 105^{5} y), which shows a thermally dependent β-decay rate. However, an astrophysically consistent interpretation requires also the knowledge of the closest neighbour isotopes involved. In particular, the 80^{80}Se(n,γ) cross section directly affects the stellar yield of the "cold" branch leading to the formation of the s-only 82^{82}Kr. Experimentally, there exists only one previous measurement on 80^{80}Se using the time of flight (TOF) technique. However, the latter suffers from some limitations that are described in this presentation. These drawbacks have been significantly improved in a recent measurement at CERN n TOF. This contribution presents a summary of the latter measurement and the status of the data analysis

    Neutron capture measurement at the n TOF facility of the 204Tl and 205Tl s-process branching points

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    Neutron capture cross sections are one of the fundamental nuclear data in the study of the s (slow) process of nucleosynthesis. More interestingly, the competition between the capture and the decay rates in some unstable nuclei determines the local isotopic abundance pattern. Since decay rates are often sensible to temperature and electron density, the study of the nuclear properties of these nuclei can provide valuable constraints to the physical magnitudes of the nucleosynthesis stellar environment. Here we report on the capture cross section measurement of two thallium isotopes, 204^{204}Tl and 205^{205}Tl performed by the time-of-flight technique at the n TOF facility at CERN. At some particular stellar s-process environments, the decay of both nuclei is strongly enhanced, and determines decisively the abundance of two s-only isotopes of lead, 204^{204}Pb and 205^{205}Pb. The latter, as a long-lived radioactive nucleus, has potential use as a chronometer of the last s-process events that contributed to final solar isotopic abundances

    Life satisfaction of women of working age shortly after breast cancer surgery

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    PURPOSE: To explore, among women of working age, satisfaction with life as a whole and with different life domains, and its associations with social and health variables, shortly after breast cancer surgery. METHODS: This cross-sectional study included 605 women, aged 20–63 years, who had had breast cancer surgery with no distant metastasis, pre-surgical chemotherapy, or previous breast cancer. Associations between LiSat-11 and demographic and social factors as well as health- and treatment-related variables were analysed by multivariable logistic regression. RESULTS: Compared with Swedish reference levels, the women were, after breast cancer surgery, less satisfied with life, particularly sexual life. Women working shortly after breast cancer surgery were more often satisfied with life in provision domains compared with the reference population. Although most included variables showed associations with satisfaction, after adjustment for all significantly associated variables, only six variables—having children, being in work, having emotional and informational social support, and having good physical and emotional functioning—were positively associated with satisfaction with life as a whole. The odds ratios for satisfaction were higher in most life domains if the woman had social support and good emotional and cognitive functioning. CONCLUSIONS: One month after breast cancer surgery, satisfaction with different life domains was associated primarily with social support and health-related functioning. However, this soon after surgery, treatment-related variables showed no significant associations with life satisfaction. These results are useful for planning interventions to enhance e.g. social support and emotional as well as cognitive functioning

    Identification of hnRNP P2 as TLS/FUS using electrospray mass spectrometry.

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    Protein complexes assembled on mRNA precursors can be separated by gel filtration chromatography to yield spliceosomal and H complex fractions (Reed R, Griffith J, Maniatis T, 1988, Cell 53:949-961; Reed R, 1990, Proc Natl Acad Sci USA 87:8031-8035.). Here we use Nano electrospray mass spectrometry (Wilm M, Mann M, 1994, Int J Mass Spectrometry Ion Processes 136:167-180) to identify proteins complexed with Adeno-pre-mRNA in the H complex peak. Four of the major hnRNP proteins, A1, B1, C1, and G, were identified by database analysis based on peptide mass and sequence information. A fifth protein in the H complex peak, corresponding to hnRNP P2, is shown to be the product of the TLS/FUS gene. This was originally identified as a chimeric oncogene formed by the chromosome translocation t(12;16) that is responsible for myxoid liposarcoma. The involvement of hnRNP P2 in oncogenesis provides a clear example of the importance of hnRNP proteins in molecular disease
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