Crystallization and preliminary X-ray diffraction analysis of levansucrase (LsdA) from Gluconacetobacter diazotrophicus SRT4

The endophytic bacterium Gluconacetobacter diazotrophicus SRT4 secretes a constitutively expressed levansucrase (LsdA; EC 2.4.1.10), which converts sucrose to fructo-oligosaccharides and levan. Fully active LsdA was purified to high homogeneity by non-denaturing reversed-phase HPLC and was crystallized at room temperature by the hanging-drop vapour-diffusion method using ammonium sulfate and ethanol as precipitants. The crystals are extremely sensitive, but native data have been collected to 2.5 A under cryogenic conditions using synchrotron radiation. LsdA crystals belong to the orthorhombic space group P22(1)2(1) or P2(1)2(1)2, with unit-cell parameters a = 53.80, b = 119.39, c = 215.10 A

Innovazione, curricolo flessibile, metodologia attiva per una scuola della durata di 12 anni

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Assembly and proteolytic processing of mycobacterial ClpP1 and ClpP2

<p>Abstract</p> <p>Background</p> <p>Caseinolytic proteases (ClpPs) are barrel-shaped self-compartmentalized peptidases involved in eliminating damaged or short-lived regulatory proteins. The <it>Mycobacterium tuberculosis </it>(MTB) genome contains two genes coding for putative ClpPs, ClpP1 and ClpP2 respectively, that are likely to play a role in the virulence of the bacterium.</p> <p>Results</p> <p>We report the first biochemical characterization of ClpP1 and ClpP2 peptidases from MTB. Both proteins were produced and purified in <it>Escherichia coli</it>. Use of fluorogenic model peptides of diverse specificities failed to show peptidase activity with recombinant mycobacterial ClpP1 or ClpP2. However, we found that ClpP1 had a proteolytic activity responsible for its own cleavage after the Arg8 residue and cleavage of ClpP2 after the Ala12 residue. In addition, we showed that the absence of any peptidase activity toward model peptides was not due to an obstruction of the entry pore by the N-terminal flexible extremity of the proteins, nor to an absolute requirement for the ClpX or ClpC ATPase complex. Finally, we also found that removing the putative propeptides of ClpP1 and ClpP2 did not result in cleavage of model peptides.</p> <p>We have also shown that recombinant ClpP1 and ClpP2 do not assemble in the conventional functional tetradecameric form but in lower order oligomeric species ranging from monomers to heptamers. The concomitant presence of both ClpP1 and ClpP2 did not result in tetradecameric assembly. Deleting the amino-terminal extremity of ClpP1 and ClpP2 (the putative propeptide or entry gate) promoted the assembly in higher order oligomeric species, suggesting that the flexible N-terminal extremity of mycobacterial ClpPs participated in the destabilization of interaction between heptamers.</p> <p>Conclusion</p> <p>Despite the conservation of a Ser protease catalytic triad in their primary sequences, mycobacterial ClpP1 and ClpP2 do not have conventional peptidase activity toward peptide models and display an unusual mechanism of self-assembly. Therefore, the mechanism underlying their peptidase and proteolytic activities might differ from that of other ClpP proteolytic complexes.</p

Políticas para dirigir a los nuevos profesionales. Motivaciones y valores de la Generación Y

Por primera vez en la historia del mercado laboral, las organizaciones acogen profesionales cuyas edades cubren un rango de más de cuarenta años. Por tanto, en un contexto en el que la gestión de la diversidad empieza a calar con fuerza dados los imperativos de negocio, nos encontramos con otro factor diferencial entre los trabajadores: la necesaria convivencia de generaciones de empleados. Para gestionar de manera adecuada y eficiente la convivencia de estas generaciones resulta imprescindible saber más acerca de las motivaciones y valores que predominan en ellas, especialmente en los recién llegados, es decir, en el grupo que podríamos denominar como recién licenciados en sentido amplio: la Generación Y. En líneas generales, entre las conclusiones de este documento se destaca la importancia que esta nueva generación otorga a la flexibilidad laboral y a la conciliación. Sus expectativas respecto al trabajo se centran en la libertad para tomar decisiones, las oportunidades de aprendizaje y desarrollo, la comunicación abierta y el respeto por su estilo de vida.Cambio generacional; globalización; estrategias de recursos humanos; motivación;

36. Diagnóstico do cancro do pulmão: comparação da expectoração pósbroncoscopia, lavado, escovado e biópsia brônquicos

Lung cancer is one of the most important respiratory diseases. The flexible bronchoscopy (FBC) is an exam widely used in its diagnosis and staging and, in specific cases, its treatment. There are several diagnostic bronchoscopies techniques currently used. The most common are the bronchial washing (BW), brushing (BBR) and biopsy (BB).It was our aim to evaluate the diagnostic yield of these three techniques, as well as, the post-bronchoscopy sputum cytology (PBSC), at presence of a suspicious visible endoscopy lesion of lung cancer. From September of 2001 to February of 2003, 56 FBC were carried out on patients with clinical history and suggestive endoscopy injury of lung cancer (hyperaemia/infiltration/tumour). In all patients we performed BW, BBR and BB and, always if it was possible, PBSC. The patients were excluded when the 4 applied diagnostic techniques were negative for malignancy. The results had been classified as positive, negative or suspected.The diagnosis of lung cancer, through at least one of three bronchoscopies techniques or PBSC, was obtained in 44 patients (78,6%). In the total of these patients the diagnostic yield from BW was 56,8%, from BBR 79,5%, from BB 95,5%. The yield from PBSC was 28,6% (n=42). The three techniques were simultaneously positive for malignancy in 52,3% of the total, being concordant, in terms of specification of the histologic type, in 69,6%. The BBR and the BB were both positive in 22,8% (70% agreement) and BW and BB in 4,5% (100% agreement). The BBR was the only positive diagnostic technique in 4,5% of the cases and the BB in 15,9%. The BW and the PBSC were never the only positive result.Of the 7 cases where the BBR was positive for malignancy but did not allow the specification of the histology type, 5 (71, 4%) were clarified by the BB. In turn, of the 7 cases where the BB was not diagnostic of the specific type of cancer, 3 were defined by BBR (42,9%).The endoscopy aspect had been described as infiltration in 63.4% cases and the remaining as tumour. The BW was more frequently positive in presence of infiltration in comparison to tumour (64% versus 36%). It were not verified significant differences in relation to the BBR and BB.In literature there continues to exist some controversy about the diagnostic value of the BW, BBR, BB and PBSC in lung cancer. This work clearly shows that the BB is the most cost-effective technique, but the values obtained for BW and BBR were also relevant. However, it is to be stressed that neither the BW nor the PBSC constituted at any time the only positive diagnostic technique for malignancy, neither did they contributed for the clarification of the histologic type. The BBR only increased by 3,5% the total diagnostic yield

Carbon Dioxide Removal and Capture for Landfill Gas Up-grading

Abstract Within the frame of an EC financially supported project - LIFE05 ENV/IT/000874 GHERL (Greenhouse Effect Reduction from Landfill)–a pilot plant was set up in order to demonstrate the feasibility of applying chemical absorption to remove carbon dioxide from landfill gas. After proper upgrading - basically removal of carbon dioxide, hydrogen sulphide, ammonia and other trace gas compound–the gas might be fed into the distribution grid for natural gas or used as vehicle fuel, replacing a fossil fuel thus saving natural resources and carbon dioxide emissions. Several experiences in Europe have been carried out concerning the landfill gas - and biogas from anaerobic digestion - quality up-grading through CO 2 removal, but in all of them carbon dioxide was vented to the atmosphere after separation, without any direct benefit in terms of greenhouse gases reduction. With respect to those previous experiences, in this work the attention was focused on CO 2 removal from landfill gas with an effective capture process, capable of removing carbon dioxide from atmosphere, through a globally carbon negative process. In particular, processes capable of producing final solid products were investigated, with the aim of obtaining as output solid compounds which can be either used in the chemical industry or disposed off. The adopted absorption process is based on using aqueous solutions of potassium hydroxide, with the final aim of producing potassium carbonate. Potassium carbonate is a product which has several applications in the chemical industry if obtained with adequate quality. It can be sold as a pulverised solid, or in aqueous solution. Several tests were carried out at the pilot plant, which was located at a landfill site, in order to feed it with a fraction of the on-site collected landfill gas. The results of the experimental campaign are reported, explained and commented in the paper. Also a discussion on economic issues is presented

Recyclable supported Pd-NHC catalytic systems for the copper free Sonogashira cross-coupling in flow

A new family of well-defined NHC-Pd complexes immobilised onto silica, alumina and titania is reported. The catalysts display activity and recyclability in the Sonogashira cross-coupling reactions under batch and continuous flow conditions. Under batch conditions the new catalytic systems were recycled up to four times with yields over 80%. These catalysts have a broad substrate scope of different aryl bromides and alkynes. The titania-supported catalysts show good conversions under continuous flow conditions at least over 8 hours on stream using MeOH as solvent.The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (EC FP7) Grant Agreement n. [NMP2-SL-2012-280827]. The authors are grateful to TECSPR14-1-0045; TECNIOspring programme, the Agency for Business Competitiveness of the Government of Catalonia, ACCIÓ, the Generalitat de Catalunya (2014SGR670). and the Spanish Ministerio de Economía y Competitividad (CTQ2016-75016-R) for financial support

Novel Insights into the Combination of Metal- and Biocatalysis: Cascade One-Pot Synthesis of Enantiomerically Pure Biaryl Alcohols in Deep Eutectic Solvents

Paris J, Rios-Lombardia N, Moris F, Gröger H, Gonzalez-Sabin J. Novel Insights into the Combination of Metal- and Biocatalysis: Cascade One-Pot Synthesis of Enantiomerically Pure Biaryl Alcohols in Deep Eutectic Solvents. CHEMCATCHEM. 2018;10(19):4417-4423.One of the pioneering examples of chemoenzymatic cascades in water such as the palladium-catalysed Suzuki-cross coupling followed by an enzymatic reduction has been revisited by the employment of a medium containing Deep Eutectic Solvents (DESs) for the catalytic performance. Thus, the unique properties of these neoteric solvents enabled to reach high substrate concentration for the overall process. Moreover, both isolated enzymes and whole cells exhibited excellent activities which allowed to obtain a set of chiral biaryl alcohols in good yields and very high enantiomeric excess (> 99%)

Questions, conjectures, and data about multiplicity lists for trees

We review and discuss a number of questions and conjectures about multiplicity lists occurring among real symmetric matrices whose graph is a tree. Our investigation is aided by a new electronic database containing all multiplicity lists for trees on fewer than 12 vertices. Some questions and conjectures are familiar and some are new, and new information is given about several. (C) 2016 Elsevier Inc. All rights reserved