192 research outputs found

    Plasmids in the aphid endosymbiont Buchnera aphidicola with the smallest genomes. A puzzling evolutionary story.

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    Buchnera aphidicola, the primary endosymbiont of aphids, has undergone important genomic and biochemical changes as an adaptation to intracellular life. The most important structural changes include a drastic genome reduction and the amplification of genes encoding key enzymes for the biosynthesis of amino acids by their translocation to plasmids. Molecular characterization through different aphid subfamilies has revealed that the genes involved in leucine and tryptophan biosynthesis show a variable fate, since they can be located on plasmids or on the chromosome in different lineages. This versatility contrasts with the genomic stasis found in three distantly related B. aphidicola strains already sequenced. We present the analysis of three B. aphidicola strains (BTg, BCt and BCc) belonging to aphids from different tribes of the subfamily Lachninae, that was estimated to harbour the bacteria with the smallest genomes. The presence of both leucine and tryptophan plasmids in BTg, a chimerical leucine-tryptophan plasmid in BCt, and only a leucine plasmid in BCc, indicates the existence of many recombination events in a recA minus bacterium. In addition, these B. aphidicola plasmids are the simplest described in this species, indicating that plasmids are also involved in the genome shrinkage process

    Robust and Cooperative Image-Based Visual Servoing System Using a Redundant Architecture

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    The reliability and robustness of image-based visual servoing systems is still unsolved by the moment. In order to address this issue, a redundant and cooperative 2D visual servoing system based on the information provided by two cameras in eye-in-hand/eye-to-hand configurations is proposed. Its control law has been defined to assure that the whole system is stable if each subsystem is stable and to allow avoiding typical problems of image-based visual servoing systems like task singularities, features extraction errors, disappearance of image features, local minima, etc. Experimental results with an industrial robot manipulator based on Schunk modular motors to demonstrate the stability, performance and robustness of the proposed system are presented

    A Comparative Analysis of 2D and 3D Tasks for Virtual Reality Therapies Based on Robotic-Assisted Neurorehabilitation for Post-stroke Patients

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    Post-stroke neurorehabilitation based on virtual therapies are performed completing repetitive exercises shown in visual electronic devices, whose content represents imaginary or daily life tasks. Currently, there are two ways of visualization of these task. 3D virtual environments are used to get a three dimensional space that represents the real world with a high level of detail, whose realism is determinated by the resolucion and fidelity of the objects of the task. Furthermore, 2D virtual environments are used to represent the tasks with a low degree of realism using techniques of bidimensional graphics. However, the type of visualization can influence the quality of perception of the task, affecting the patient's sensorimotor performance. The purpose of this paper was to evaluate if there were differences in patterns of kinematic movements when post-stroke patients performed a reach task viewing a virtual therapeutic game with two different type of visualization of virtual environment: 2D and 3D. Nine post-stroke patients have participated in the study receiving a virtual therapy assisted by PUPArm rehabilitation robot. Horizontal movements of the upper limb were performed to complete the aim of the tasks, which consist in reaching peripheral or perspective targets depending on the virtual environment shown. Various parameter types such as the maximum speed, reaction time, path length, or initial movement are analyzed from the data acquired objectively by the robotic device to evaluate the influence of the task visualization. At the end of the study, a usability survey was provided to each patient to analysis his/her satisfaction level. For all patients, the movement trajectories were enhanced when they completed the therapy. This fact suggests that patient's motor recovery was increased. Despite of the similarity in majority of the kinematic parameters, differences in reaction time and path length were higher using the 3D task. Regarding the success rates were very similar. In conclusion, the using of 2D environments in virtual therapy may be a more appropriate and comfortable way to perform tasks for upper limb rehabilitation of post-stroke patients, in terms of accuracy in order to effectuate optimal kinematic trajectories

    A Minor Role of Host Fruit on the Parasitic Performance of Aganaspis daci (Hymenoptera: Figitidae) on Medfly Larvae

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    Host fruit is known to strongly affect the performance of both fruit pests and their potential natural enemies. This is particularly important in the control of tephritid fruit flies, whose larvae develop inside the fruit and thus create a set of foraging problems for parasitoids. In the present study, we assessed the response of female Aganaspis daci (Weld) (Hymenoptera: Figitidae), one of the most promising parasitoids for tephritid biocontrol in the Mediterranean Basin, to different potential host fruit species. We measured the olfactory response to medfly-infested and uninfested fruits, and several biological parameters of A. daci when different infested fruits were offered under both laboratory and greenhouse conditions. Our results showed that this parasitoid was significantly more attracted to apples and uninfested fruit. Moreover, parasitic activity was similar among the tested fruits under both conditions, showing very high values in the laboratory and a much poorer performance when conditions were variable. This suggests that A. daci may be a good candidate to be included in mass releases against the medfly regardless of the affected crop, but only when climate conditions are not expected to hinder its normal activity

    Maternal Pre-Pregnancy Obesity Is Associated with Altered Placental Transcriptome

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    <p><b>(A)</b> Principal component analysis (PCA) of term placental gene expression profiles in obese (Ob_ N°) and normal weight women (N_N°). <b>(B)</b> Cluster analysis of dysregulated genes in term placentas from obese (Ob_ N°) <i>vs</i>. normal weight women (N_N°). Red represents genes with high expression levels and green represents genes with low expression levels.</p

    MiRNA Expression Profile of Human Subcutaneous Adipose and during Adipocyte Differentiation

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    BACKGROUND: Potential regulators of adipogenesis include microRNAs (miRNAs), small non-coding RNAs that have been recently shown related to adiposity and differentially expressed in fat depots. However, to date no study is available, to our knowledge, regarding miRNAs expression profile during human adipogenesis. Thereby, the aim of this study was to investigate whether miRNA pattern in human fat cells and subcutaneous adipose tissue is associated to obesity and co-morbidities and whether miRNA expression profile in adipocytes is linked to adipogenesis. METHODOLOGY/PRINCIPAL FINDINGS: We performed a global miRNA expression microarray of 723 human and 76 viral mature miRNAs in human adipocytes during differentiation and in subcutaneous fat samples from non-obese (n = 6) and obese with (n = 9) and without (n = 13) Type-2 Diabetes Mellitus (DM-2) women. Changes in adipogenesis-related miRNAs were then validated by RT-PCR. Fifty of 799 miRNAs (6.2%) significantly differed between fat cells from lean and obese subjects. Seventy miRNAs (8.8%) were highly and significantly up or down-regulated in mature adipocytes as compared to pre-adipocytes. Otherwise, 17 of these 799 miRNAs (2.1%) were correlated with anthropometrical (BMI) and/or metabolic (fasting glucose and/or triglycerides) parameters. We identified 11 miRNAs (1.4%) significantly deregulated in subcutaneous fat from obese subjects with and without DM-2. Interestingly, most of these changes were associated with miRNAs also significantly deregulated during adipocyte differentiation. CONCLUSIONS/SIGNIFICANCE: The remarkable inverse miRNA profile revealed for human pre-adipocytes and mature adipocytes hints at a closely crosstalk between miRNAs and adipogenesis. Such candidates may represent biomarkers and therapeutic targets for obesity and obesity-related complications

    Life History Parameters of Diachasmimorpha longicaudata on Ceratitis capitata Under Laboratory Conditions: Implications for Mass Rearing and Biological Control

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    The Mediterranean fruit fly, Ceratitis capitata, is considered one of the most destructive pests worldwide. The braconid Diachasmimorpha longicaudata is the most widely used parasitoid in biological control programs of tephritids. It has been mass-reared and used in augmentative releases against major fruit fly species in tropical and subtropical countries, and recently in the Mediterranean Basin. After its introduction into Spain and then Tunisia, reproductive and demographic parameters have been studied on C. capitata under laboratory conditions. These parameters were compared to those published elsewhere. The role of artificial diet for rearing the host is discussed. Our findings showed the good fitness of the parasitoids produced on C. capitata in laboratory with a generation time of 28.1 days, a reproductive rate of 39.2, an intrinsic rate of increase of 0.125, a doubling time of 5.2 days and the finite rate of increase (per day) was 1. Involvements on the biological control of the Mediterranean fruit fly in Tunisia are discussed
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