979 resultados para Thiazole derivative
Resumo:
This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem
Resumo:
This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem
Resumo:
This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem
Resumo:
This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem
Resumo:
This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem
Resumo:
Osakemarkkinoilta on jo useiden vuosien ajan julkaistu lukuisia tutkimuksia, joissa on esitetty havaintoja ajallisesta säännönmukaisuudesta osakkeiden hinnoissa, joita ei pystytä selittämään markkinakohtaisilla fundamenteilla. Nämä niin kutsutut kalenterianomaliat esiintyvät tyypillisesti ajallisissa käännepisteissä, kuten vuoden, kuukauden tai viikon vaihtuessa seuraavaksi. Myös erilaisten katkosten, kuten juhlapyhien, kaupankäyntirutiineissa on havaittu aiheuttavan anomalioita. Tutkimuksen tavoitteena oli tutkia osakemarkkinoilla havaittujen kalenterianomalioiden esiintymistä pohjoismaisilla sähkömarkkinoilla. Tutkitut anomaliat olivat viikonpäivä- kuukausi-, kuunvaihde- ja juhlapyhäanomalia. Näiden lisäksi tutkittiin tuottojen käyttäytymistä optioiden erääntymispäivien läheisyydessä. Yksittäisten tuotteiden sijasta tarkastelut suoritettiin sesonki- ja kvartaalituotteista muodostetuilla vuosituotteilla. Testauksessa käytettiin pienimmän neliösumman menetelmää, huomioidenheteroskedastisuuden, autokorrelaation ja multikollineaarisuuden vaikutukset. Pelkkien kalenterimuuttujien lisäksi testit suoritettiin regressiomalleilla, joissa lisäselittäjinä käytettiin spot-hintaa, päästöoikeuden hintaa ja/tai sade-ennusteita. Tarkastelujakso koostui vuosista 1998-2006.
Resumo:
Résumé: Dans le but de rechercher de nouveaux composés naturels à intérêt thérapeutique, les extraits dichlorométhanique et méthanolique de Zanthoxylum zanthoxyloides (Lam.) Zepernick et Timler (Syn. Fagara zanthoxyloides L.) (Rutaceae), une brosse à dents africaine ont été soumis à un criblage chimique et biologique. Un dépistage des activités: antifongiques contre le champignon phytopathogène Cladosporium cucumerinum et la levure commensale responsable de mycoses chez l'homme Candida albicans, antibactérienne contre la bactérie opportuniste Bacillus subtilis, larvicide contre le moustique vecteur de la fièvre jaune Aedes aegypti et molluscicide contre Biomphalaria glabrata, un escargot impliqué dans la transmission de la schistosomiase urinaire a été réalisé. Les propriétés antiradicalaires et inhibitrices de l'acétylcholinestérase de ces extraits ont aussi été dépistées. Sur la base des résultats obtenus lors de ce screening, l'investigation phytochimique de ces extraits a été entreprise. Elle a abouti à l'isolement de 14 composés, actifs pour la majorité contre Cladosporium cucumerinum et Bacillus subtilis, dont la structure a été établie au moyen de méthodes spectroscopiques (UV, MS, IR, 1H- et 13C-NMR). Des méthodes chimiques (hydrolyse, acétylation) ont été requises pour la confirmation de structures. L'extrait dichlorométhanique a fourni un nouveau composé, un dérivé du phényléthane, ainsi que dix composés connus, dont trois dérivés du phénylpropane, un lignane, un alcaloïde de la famille des benzophénanthridines, un triterpène, deux amides phénoliques et deux amides oléfmiques. L'extrait méthanolique a fourni un nouveau composé avec une fonction endoperoxyde, qui avait montré une activité inhibitrice modérée de l'acétylcholinestérase, ainsi que l'hespéridine et un dérivé de la chélérythrine. Par ailleurs, l'analyse LC/UV/APC1-MS de cet extrait a permis de détecter on-une sept produits connus. Parmi ces composés, se trouvent l'acide divanilloylquinique, la chélérythrine et quatre de ses dérivés: norchélérythrin.e, 6-(2-oxybutyl) dihydrochélérythrine, 6-hydroxy-dihydrochélérythrine et avicine, ainsi qu'une amide phénolique, l'amottianamide. La présence de ces dérivés de la chélérythrine a été mise en évidence dans deux autres espèces du même genre lors d'une étude LC/UV/APCI-MS comparative. Les activités fongicides contre Cladosporium cucumerinum et Candida albicans et bactéricides contre Bacillus subtilis et Streptococcus mutans ATCC 25175, mises en évidence sur plaque CCM et par les tests de dilution dans l'agar de ces composés, permettent de justifier l'utilisation de Zanthoxylum zanthoxyloides (Lam.) Zepemick et Timler comme brosse à dents africaine. Les techniques couplées de pointe utilisées dans cette étude ont montré leur apport inestimable dans le domaine de la recherche phytochimique et les applications futures dans le domaine de déréplication d'extraits bruts. Abstract: With the aim of discovering new natural therapeutics, the dichloromethane and methanol extracts of the African toothbrush tree Zanthoxylum zanthoxyloides (Lam.) Zepernick et Timler (Syn. Fagara zanthoxyloides L.) (Rutaceae), were submitted to biological and chemical assays. The former included: the antifimgal activities of the extracts against the phytopathogenic fungus Cladosporium cucumerinum, the commensal yeast which causes human mycoses Candida albicans, the bactericidal activity against the opportunistic bacteria Bacillus subtilis, the larvicidal activity against the yellow fever-transmitting mosquito Aedes aegypti and the molluscicidal effect on the snail Biomphalaria glabrata involved in the transmission of urinary schistosomiasis. The antiradical and acetylcholinesterase-inhibiting properties of these extracts were also investigated. On the basis of these results, a phytochemical investigation of the dichloromethane and methanol extracts of Zanthoxylum zanthoxyloides was undertaken. Their fractionation led to the isolation of 14 compounds, the majority of which were active against Cladosporium cucumerinum and Bacillus subtilis, whose structures were elucidated by spectroscopic techniques (UV, MS, IR, 1H- and 13C-NMR). Chemical methods (hydrolysis, acetylation) were performed to confirm the structures. The dichloromethane extract yielded a new phenylethane derivative, together with ten known compounds: three phenylpropane derivatives, a lignan, a benzophenanthridine alkaloid, a triterpene and four phenolic and olefinic amides. The methanol extract yielded a new compound with an endoperoxide moiety, which showed moderate acetylcholinesterase-inhibiting activity, together with hesperidin and a chelerythrine derivative. Seven more compounds were detected on-line by LC/UV/APCI-MS. Among the compounds detected were divanilloylquinic acid, chelerythrine and four chelerythrine derivatives: norchelerythrine, 6-(2-oxybuty1)-dihydrochelerythrine, 6-hydroxy dihydrochelerythrine and avicine, together with the phenolic amide amottianamide. Most of the chelerythrine derivatives were also found in two other Zanthoxylum species following LC/UV/APCI-MS analysis. The antifungal activities against Cladosporium cucumerinum and Candida albicans and antibacterial activities against Bacillus subtilis and Streptococcus mutans ATCC 25175, may explain the utilization in traditional medicine of the roots of this plant as a toothbrush. The advanced hyphenated techniques used in this study showed their inestimable contribution to the field of phytochemical research and applications in the field of dereplication of crude extracts.
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Résumé: Pratiquement tous les cancers du colon contiennent des mutations dans la voie de signalisation de Wnt qui active constitutivement cette voie. Cette activation mène à la stabilisation de la β-catenine. La β-catenin est transportée dans le noyau ou elle active des gènes cible en interagissant avec le facteur de transcription de TCF/LEF. Des adénovirus qui peuvent sélectivement se répliquer dans les cellules tumorales sont les agents qui peuvent permettre la déstruction de la tumeur mais pas le tissu normal. In vitro, les adénovirus avec des sites d'attachement du facteur de transcription TCF dans les promoteurs de l'adénovirus montrent une sélectivité et une activité dans une large sélection de lignées cellulaires de cancer du colon. Au contraire, in vivo, quand les adénovirus modifiés sont injectés dans la circulation, ils sont moins efficaces à cause de leur fixation par le foie et à cause de l'absence d'expression du récepteur du Coxsackie-Adénovirus (CAR). Le but de ma thèse était de modifier la protéine principale de capside de l'adénovirus, fibre, pour augmenter l'infection des tumeurs du cancer du colon. La fibre de l'adénovirus est responsable de l'attachement aux cellules et de l'entrée virale. J'ai inséré un peptide RGD dans la boucle HI de la fibre qui dirige sélectivement le virus aux récepteurs des integrines. Les integrines sont surexprimées par les cellules du cancer du colon et l'endothélium des vesseaux de la tumeur. Le virus re-ciblé, vKH6, a montré une activité accrue dans toutes les lignées cellulaires de cancer du colon, tandis que la sélectivité était maintenue. In vivo, vKH6 était supérieur au virus avec une capside de type sauvage en retardant la croissance de la tumeur. Le virus s'est répliqué plus vite et dispersé graduellement dans la tumeur. Cet effet a été montré par hybridation in situ et par PCR quantitative. Cependant, la monothérapie avec le virus n'a pu retarder la croissance des cellules tumorales SW620 greffées que de 2 semaines, mais à cause des régions non infectées la tumeur n'a pas pu être éliminée. Bien que la combinaison avec les chimiothérapies conventionnelles soit d'intérêt potentiel, presque toutes interfèrent avec la réplication virale. Les drogues antiangiogéniques sont des agents anti-tumoraux efficaces et prometteurs. Ces drogues n'interfèrent pas avec le cycle de vie de l'adénovirus. RAD001 est un dérivé de la rapamycine et il inhibe mTOR, une protéine kinase de la voie de PI3K. RAD001 empêche la croissance des cellules et il a aussi des effets anti-angiogénique et immunosuppressifs. RAD001 in vitro n'affecte pas l'expression des gènes viraux et la production virale. La combinaison de VKH6 et RAD001 in vivo a un effet additif en retardant la croissance de la tumeur. Des nouveaux peptides plus efficaces dans le ciblage de l'adénovirus sont nécessaires pour augmenter l'infection des tumeurs. J'ai créé un système de recombinaison qui permettra la sélection de nouveaux peptides dans le contexte du génome de l'adénovirus. Summary Virtually all colon cancers have mutations in the Wnt signalling pathway which result in the constitutive activation of the pathway. This activation leads to stabilization of β-catenin. β-catenin enters the nucleus and activates its target genes through interaction with the TCF transcription factor. Selectively replicating adenoviruses are promising novel agents that can destroy the tumour but not the surrounding normal tissue. In vitro, adenoviruses with TCF binding sites in the early viral promoters show selectivity and activity in a broad panel of viruses but in vivo they are less effective due to the lack of expression of the Coxsackie-Adenovirus receptor (CAR). The aim of my thesis was to modify the major capsid protein of the adenovirus, fibre, to increase the infection of colon tumours. Fibre of adenovirus is responsible for the binding to cells and for the viral uptake. I inserted an RGD binding peptide into the HI loop of fibre that selectively targets the virus to integrins that are overexpressed on tumour cells and on tumour endothelium. The retargeted virus, vKH6, showed increased activity in all colon cancer cell lines while selectivity was maintained. In vivo, vKH6 is superior to a matched virus with a wild type capsid in delaying tumour growth. vKH6 replicates and gradually spreads within the tumour as shown by in situ hybridization and Q-PCR. The virus alone can delay the growth of SW620 xenografts by 2 weeks but due to uninfected tumour regions the tumour cannot be cured. Although combination with conventional chemotherapeutics is of potential interest, almost all of them interfere with the viral replication. Growing evidence supports that anti-angiogenic drugs are effective and promising anti-tumour agents. These drugs interfere less with the viral life cycle. RAD001 is a rapamycin derivative and it blocks mTOR, a protein kinase in the PI3K pathway. RAD001 inhibits cell growth and has strong anti-angiogenic and immunosuppressive effects. RAD001 in vitro does not affect viral gene expression and viral burst size. In vivo vKH6 and RAD001 have an additive effect in delaying tumour growth, but tumour growth is still not completely inhibited. To further increase tumour infection new tumour specific targeting peptides are needed. I created an adenovirus display library that will allow the selection of targeting peptides. This system may also facilitate the production of fibre modified viruses.
Resumo:
In order that the radius and thus ununiform structure of the teeth and otherelectrical and magnetic parts of the machine may be taken into consideration the calculation of an axial flux permanent magnet machine is, conventionally, doneby means of 3D FEM-methods. This calculation procedure, however, requires a lotof time and computer recourses. This study proves that also analytical methods can be applied to perform the calculation successfully. The procedure of the analytical calculation can be summarized into following steps: first the magnet is divided into slices, which makes the calculation for each section individually, and then the parts are submitted to calculation of the final results. It is obvious that using this method can save a lot of designing and calculating time. Thecalculation program is designed to model the magnetic and electrical circuits of surface mounted axial flux permanent magnet synchronous machines in such a way, that it takes into account possible magnetic saturation of the iron parts. Theresult of the calculation is the torque of the motor including the vibrations. The motor geometry and the materials and either the torque or pole angle are defined and the motor can be fed with an arbitrary shape and amplitude of three-phase currents. There are no limits for the size and number of the pole pairs nor for many other factors. The calculation steps and the number of different sections of the magnet are selectable, but the calculation time is strongly depending on this. The results are compared to the measurements of real prototypes. The permanent magnet creates part of the flux in the magnetic circuit. The form and amplitude of the flux density in the air-gap depends on the geometry and material of the magnetic circuit, on the length of the air-gap and remanence flux density of the magnet. Slotting is taken into account by using the Carter factor in the slot opening area. The calculation is simple and fast if the shape of the magnetis a square and has no skew in relation to the stator slots. With a more complicated magnet shape the calculation has to be done in several sections. It is clear that according to the increasing number of sections also the result will become more accurate. In a radial flux motor all sections of the magnets create force with a same radius. In the case of an axial flux motor, each radial section creates force with a different radius and the torque is the sum of these. The magnetic circuit of the motor, consisting of the stator iron, rotor iron, air-gap, magnet and the slot, is modelled with a reluctance net, which considers the saturation of the iron. This means, that several iterations, in which the permeability is updated, has to be done in order to get final results. The motor torque is calculated using the instantaneous linkage flux and stator currents. Flux linkage is called the part of the flux that is created by the permanent magnets and the stator currents passing through the coils in stator teeth. The angle between this flux and the phase currents define the torque created by the magnetic circuit. Due to the winding structure of the stator and in order to limit the leakage flux the slot openings of the stator are normally not made of ferromagnetic material even though, in some cases, semimagnetic slot wedges are used. In the slot opening faces the flux enters the iron almost normally (tangentially with respect to the rotor flux) creating tangential forces in the rotor. This phenomenon iscalled cogging. The flux in the slot opening area on the different sides of theopening and in the different slot openings is not equal and so these forces do not compensate each other. In the calculation it is assumed that the flux entering the left side of the opening is the component left from the geometrical centre of the slot. This torque component together with the torque component calculated using the Lorenz force make the total torque of the motor. It is easy to assume that when all the magnet edges, where the derivative component of the magnet flux density is at its highest, enter the slot openings at the same time, this will have as a result a considerable cogging torque. To reduce the cogging torquethe magnet edges can be shaped so that they are not parallel to the stator slots, which is the common way to solve the problem. In doing so, the edge may be spread along the whole slot pitch and thus also the high derivative component willbe spread to occur equally along the rotation. Besides forming the magnets theymay also be placed somewhat asymmetric on the rotor surface. The asymmetric distribution can be made in many different ways. All the magnets may have a different deflection of the symmetrical centre point or they can be for example shiftedin pairs. There are some factors that limit the deflection. The first is that the magnets cannot overlap. The magnet shape and the relative width compared to the pole define the deflection in this case. The other factor is that a shifting of the poles limits the maximum torque of the motor. If the edges of adjacent magnets are very close to each other the leakage flux from one pole to the other increases reducing thus the air-gap magnetization. The asymmetric model needs some assumptions and simplifications in order to limit the size of the model and calculation time. The reluctance net is made for symmetric distribution. If the magnets are distributed asymmetrically the flux in the different pole pairs will not be exactly the same. Therefore, the assumption that the flux flows from the edges of the model to the next pole pairs, in the calculation model from one edgeto the other, is not correct. If it were wished for that this fact should be considered in multi-pole pair machines, this would mean that all the poles, in other words the whole machine, should be modelled in reluctance net. The error resulting from this wrong assumption is, nevertheless, irrelevant.
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In the era of fast product development and customized product requirements, the concept of product platform has proven its power in practice. The product platform approach has enabledcompanies to increase the speed of product introductions while simultaneously benefit from efficiency and effectiveness in the development and production activities. The product platforms are technological bases, which can be used to develop several derivative products, and hence, the differentiation can be pushed closer to the product introduction. The product platform development has some specific features, which differ somewhat from the product development of single products. The time horizon is longer, since the product platform¿slife cycle is longer than individual product's. The long time-horizon also proposes higher market risks and the use of new technologies increases the technological risks involved. The end-customer interface might be far away, but there is not a lack of needs aimed at the product platforms ¿ in fact, the product platform development is very much balancing between the varying needs set to it by thederivative products. This dissertation concentrated on product platform development from the internal product lines' perspective of a singlecase. Altogether six product platform development factors were identified: 'Strategic and business fit of product platform', 'Project communication and deliverables', 'Cooperation with product platform development', 'Innovativeness of product platform architecture and features', 'Reliability and quality of product platform', and 'Promised schedules and final product platform meeting the needs'. From the six factors, three were found to influence quite strongly the overall satisfaction, namely 'Strategic and business fit of product platform', 'Reliability and quality of product platform', and 'Promised schedules and final product platform meeting the needs'. Hence, these three factors might be the ones a new product platform development unit should concentrate first in order to satisfy their closest customers, the product lines. The 'Project communication and deliverables' and 'Innovativeness of product platform architecture and features' were weaker contributors to the overall satisfaction. Overall, the factors explained quite well the satisfaction of the product lines with product platform development. Along the research, several interesting aspects about the very basic nature of the product platform development were found. The long time horizon of the product platform development caused challenges in the area of strategic fIT - a conflict between the short-term requirements and long term needs. The fact that a product platform was used as basis of several derivative products resulted into varying needs, and hence the match with the needs and the strategies. The opinions, that the releases of the larger product lines were given higher priorities, give an interesting contribution to the strategy theory of powerand politics. The varying needs of the product lines, the strengths of them as well as large number of concurrent releases set requirements to prioritization. Hence, the research showed the complicated nature of the product platform development in the case unIT - the very basic nature of the product platform development might be its strength (gaining efficiency and effectiveness in product development and product launches) but also the biggest challenge (developing products to meet several needs). As a single case study, the results of this research are not directly generalizable to all the product platform development activities. Instead, the research serves best as a starting point for additional research as well as gives some insights about the factors and challengesof one product development unit.
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Concerning process control of batch cooling crystallization the present work focused on the cooling profile and seeding technique. Secondly, the influence of additives on batch-wise precipitation process was investigated. Moreover, a Computational Fluid Dynamics (CFD) model for simulation of controlled batch cooling crystallization was developed. A novel cooling model to control supersaturation level during batch-wise cooling crystallization was introduced. The crystallization kinetics together with operating conditions, i.e. seed loading, cooling rate and batch time, were taken into account in the model. Especially, the supersaturation- and suspension density- dependent secondary nucleation was included in the model. The interaction between the operating conditions and their influence on the control target, i.e. the constant level of supersaturation, were studied with the aid of a numerical solution for the cooling model. Further, the batch cooling crystallization was simulated with the ideal mixing model and CFD model. The moment transformation of the population balance, together with the mass and heat balances, were solved numerically in the simulation. In order to clarify a relationship betweenthe operating conditions and product sizes, a system chart was developed for anideal mixing condition. The utilization of the system chart to determine the appropriate operating condition to meet a required product size was introduced. With CFD simulation, batch crystallization, operated following a specified coolingmode, was studied in the crystallizers having different geometries and scales. The introduced cooling model and simulation results were verified experimentallyfor potassium dihydrogen phosphate (KDP) and the novelties of the proposed control policies were demonstrated using potassium sulfate by comparing with the published results in the literature. The study on the batch-wise precipitation showed that immiscible additives could promote the agglomeration of a derivative of benzoic acid, which facilitated the filterability of the crystal product.
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This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem
Resumo:
This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem
Resumo:
This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem
Resumo:
En el imaginario colectivo de la sociedad de posguerra siempre están presentes las duras condiciones de la vida cotidiana. La población infantil fue especialmente sensible a esta situación debido al alto índice de enfermedades infecciosas, el racionamiento dietético y las angustias derivadas del conflicto bélico. En estas condiciones, el Auxilio Social de la Falange fue el encargado de administrar la beneficencia y, a su vez, resocializar la población, en este caso, la infantil, dentro de los valores nacionalsindicalistas y nacionalcatólicos. Ello le permitió no sólo controlar la política social sino también criminalizar a los vencidos en el momento de administrarla. En definitiva, fue uno de los pilares fundamentales en el proceso de construcción del edificio franquista.