935 resultados para Manipulation néonatale


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We describe a transgenic mouse line carrying the cre transgene under the control of the adenovirus EIIa promoter that targets expression of the Cre recombinase to the early mouse embryo. To assess the ability of this recombinase to excise loxP-flanked DNA sequences at early stages of development, we bred EIIa-cre transgenic mice to two different mouse lines carrying loxP-flanked target sequences: (i) a strain with a single gene-targeted neomycin resistance gene flanked by 1oxP sites and (ii) a transgenic line carrying multiple transgene copies with internal loxP sites. Mating either of these loxP-carrying mouse lines to EIIa-cre mice resulted in first generation progeny in which the loxP-flanked sequences had been efficiently deleted from all tissues tested, including the germ cells. Interbreeding of these first generation progeny resulted in efficient germ-line transmission of the deletion to subsequent generations. These results demonstrate a method by which loxP-flanked DNA sequences can be efficiently deleted in the early mouse embryo. Potential applications of this approach are discussed, including reduction of multicopy transgene loci to produce single-copy transgenic lines and introduction of a variety of subtle mutations into the line.

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Transposon Tn1000 has been adapted to deliver novel DNA sequences for manipulating recombinant DNA. The transposition procedure for these "tagged" Tn1000s is simple and applicable to most plasmids in current use. For yeast molecular biology, tagged Tn1000s introduce a variety of yeast selective markers and replication origins into plasmids and cosmids. In addition, the beta-globin minimal promoter and lacZ gene of Tn(beta)lac serve as a mobile reporter of eukaryotic enhancer activity. In this paper, Tn(beta)lac was used to localize a mouse HoxB-complex enhancer in transgenic mice. Other tagged transposons create Gal4 DNA-binding-domain fusions, in either Escherichia coli or yeast plasmids, for use in one- and two-hybrid tests of transcriptional activation and protein-protein interaction, respectively. With such fusions, the Saccharomyces cerevisiae Swi6 G1/S-phase transcription factor and the Xenopus laevis Pintallavis developmental regulator are shown to activate transcription. Furthermore, the same transposon insertions also facilitated mapping of the Swi6 and Pintallavis domains responsible for transcriptional activation. Thus, as well as introducing novel sequences, tagged transposons share the numerous other applications of transposition such as producing insertional mutations, creating deletion series, or serving as mobile primer sites for DNA sequencing.

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Bacille Calmette-Guérin (BCG) is a live, attenuated strain of Mycobacterium bovis used widely for tuberculosis prophylaxis and bladder cancer immunotherapy, although it has limitations in both contexts. To investigate whether BCG's immunostimulatory properties could be modified, and to gain insight into the interaction between mycobacteria and their hosts, we constructed recombinant BCG strains that secrete functional murine cytokines and studied their properties in mouse models of experimental infection. Cell-mediated immune responses to mycobacterial antigen (purified protein derivative) were assayed using splenocytes from mice inoculated with various BCG recombinants. Antigen-specific proliferation and cytokine release were found to be substantially greater with splenocytes derived from mice injected with cytokine-secreting BCG than with splenocytes from mice injected with BCG lacking cytokines. The most profound effects were induced by BCG secreting interleukin 2, interferon gamma, or granulocyte-macrophage colony-stimulating factor. Thus, cytokine-secreting BCG can enhance immune responses to mycobacterial antigens and may be improved reagents for tuberculosis prophylaxis and cancer immunotherapy.

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Tactile sensors play an important role in robotics manipulation to perform dexterous and complex tasks. This paper presents a novel control framework to perform dexterous manipulation with multi-fingered robotic hands using feedback data from tactile and visual sensors. This control framework permits the definition of new visual controllers which allow the path tracking of the object motion taking into account both the dynamics model of the robot hand and the grasping force of the fingertips under a hybrid control scheme. In addition, the proposed general method employs optimal control to obtain the desired behaviour in the joint space of the fingers based on an indicated cost function which determines how the control effort is distributed over the joints of the robotic hand. Finally, authors show experimental verifications on a real robotic manipulation system for some of the controllers derived from the control framework.

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During grasping and intelligent robotic manipulation tasks, the camera position relative to the scene changes dramatically because the robot is moving to adapt its path and correctly grasp objects. This is because the camera is mounted at the robot effector. For this reason, in this type of environment, a visual recognition system must be implemented to recognize and “automatically and autonomously” obtain the positions of objects in the scene. Furthermore, in industrial environments, all objects that are manipulated by robots are made of the same material and cannot be differentiated by features such as texture or color. In this work, first, a study and analysis of 3D recognition descriptors has been completed for application in these environments. Second, a visual recognition system designed from specific distributed client-server architecture has been proposed to be applied in the recognition process of industrial objects without these appearance features. Our system has been implemented to overcome problems of recognition when the objects can only be recognized by geometric shape and the simplicity of shapes could create ambiguity. Finally, some real tests are performed and illustrated to verify the satisfactory performance of the proposed system.

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This dissertation relates job desires and outcomes to the Dark Personality (Psychopathy, Machiavellianism, Narcissism, Low Agreeableness, Low Honesty-Humility) in the United States Army. It purports that individuals high on the Dark Personality desire more power, money, and status, and that they obtain jobs that afford them these luxuries by using manipulation at work. Two pilot studies used samples of United States Army members to create and test index variables: Dark Personality, Total Manipulation in the workplace, Desire for Job Success, and Total Job Success in the Army. Individual personality traits, manipulation tactics, and job desires were examined in secondary analyses. Using a sample of 468 United States Army Members, central analyses indicated that Army members high on the Dark Personality desired Job Success. Likewise, army members higher on the Dark Personality used more Manipulation tactics at work, including the egregious tactics. Yet, using more Manipulation tactics at work predicted lower levels of Job Success in the Army. Most manipulation tactics had a negative impact on Job Success, with the exception of soft tactics like Reason and Responsibility Invocation. Together, these results indicate that selective use of soft manipulation predicted Job Success, but use of more manipulation tactics predicted less Job Success in the Army. Curvilinear results indicated that being either very low or very high on the Dark Personality predicted more Job Success in the Army, whereas having intermediate levels of the Dark Personality predicted less Job Success. Finally, possessing the Dark Personality and using more Manipulation tactics at work, together, predicted less Job Success in the Army. Collectively, the results indicate that army members with intermediate levels of the Dark Personality want more powerful and high paying jobs, yet their strategy of manipulating their coworkers to move up the job ladder does not result in higher ranking, higher paying Army positions. However, Army members highest on the Dark Personality achieved job success, defying the maladaptive influence that antisocial personality traits and manipulative behaviour had on job success for most Army members. Therefore, this dissertation indicates that successful corporate scoundrels exist in the Army, but there are few of them.

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The aim of this paper is to analyse the proposed Directive on criminal sanctions for insider dealing and market manipulation (COM(2011)654 final), which represents the first exercise of the European Union competence provided for by Article 83(2) of the Treaty on the Functioning of the European Union. The proposal aims at harmonising the sanctioning regimes provided by the Member States for market abuse, imposing the introduction of criminal sanctions and providing an opportunity to critically reflect on the position taken by the Commission towards the use of criminal law. The paper will discuss briefly the evolution of the EU’s criminal law competence, focusing on the Lisbon Treaty. It will analyse the ‘essentiality standard’ for the harmonisation of criminal law included in Article 83(2) TFEU, concluding that this standard encompasses both the subsidiarity and the ultima ratio principles and implies important practical consequences for the Union’s legislator. The research will then focus on the proposed Directive, trying to assess if the Union’s legislator, notwithstanding the ‘symbolic’ function of this proposal in the financial crisis, provides consistent arguments on the respect of the ‘essentiality standard’. The paper will note that the proposal raises some concerns, because of the lack of a clear reliance on empirical data regarding the essential need for the introduction of criminal law provisions. It will be stressed that only the assessment of the essential need of an EU action, according to the standard set in Article 83(2) TFEU, can guarantee a coherent choice of the areas interested by the harmonisation process, preventing the legislator to choose on the basis of other grounds.

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The mammalian gut microbiota harbors a diverse ecosystem where hundreds of bacterial species interact with each other and their host. Given that bacteria use signals to communicate and regulate group behaviors (quorum sensing), we asked whether such communication between different commensal species can influence the interactions occurring in this environment. We engineered the enteric bacterium, Escherichia coli, to manipulate the levels of the interspecies quorum sensing signal, autoinducer-2 (AI-2), in the mouse intestine and investigated the effect upon antibiotic-induced gut microbiota dysbiosis. E. coli that increased intestinal AI-2 levels altered the composition of the antibiotic-treated gut microbiota, favoring the expansion of the Firmicutes phylum. This significantly increased the Firmicutes/Bacteroidetes ratio, to oppose the strong effect of the antibiotic, which had almost cleared the Firmicutes. This demonstrates that AI-2 levels influence the abundance of the major phyla of the gut microbiota, the balance of which is known to influence human health.

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The merozoite stage of the malaria parasite that infects erythrocytes and causes the symptoms of the disease is initially formed inside host hepatocytes. However, the mechanism by which hepatic merozoites reach blood vessels (sinusoids) in the liver and escape the host immune system before invading erythrocytes remains unknown. Here, we show that parasites induce the death and the detachment of their host hepatocytes, followed by the budding of parasite-filled vesicles (merosomes) into the sinusoid lumen. Parasites simultaneously inhibit the exposure of phosphatidylserine on the outer leaflet of host plasma membranes, which act as "eat me" signals to phagocytes. Thus, the hepatocyte-derived merosomes appear to ensure both the migration of parasites into the bloodstream and their protection from host immunity.

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The generation of rodent Plasmodium strains expressing fluorescent proteins in all life cycle stages has had a big impact on malaria research. With this tool in hand, for the first time it was possible to follow in real time by in vivo microscopy the infection route of Plasmodium sporozoites transmitted to the mammalian host by Anopheles mosquitoes. Recently, this work has been extended to the analysis of both hepatocyte infection by Plasmodium sporozoites, as well as liver merozoite transport into blood vessels. The stunning results of these studies have considerably changed our understanding of hepatocyte invasion and parasite liberation. Here, we describe the most important findings of the last years and in addition, we elaborate on the molecular events during the intracellular development of Plasmodium exoerythrocytic forms that give rise to erythrocyte infecting merozoites.

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Thesis (M.S.)--University of Illinois at Urbana-Champaign, 1975.