Liposarcome dorsal: aspect clinique rare

Décrit la première fois par Virchow en 1860, le liposarcome est une tumeur mésenchymateuse rare. Cette rareté est relative car les liposarcomes représentent quand même 14 à 18 % de l'ensemble des tumeurs malignes des parties molles et ils constituent le plus fréquent des sarcomes des parties molles. Pour la majorité des auteurs, il ne se développerait jamais sur un lipome ou une lipomatose préexistant. Nous rapportons un cas de volumineux liposarcome de la face dorsale du tronc. L'histoire de la maladie, l'aspect clinique inhabituel « de tumeur dans tumeur », l'aspect de la pièce opératoire nous fait évoquer la possibilité de la transformation maligne d'un lipome bénin préexistant

Evaluation of the Potential of Some Essential Oils in Biological Control against Phytopathogenic Agent Pseudomonas syringae pv. Tomato DC3000 Responsible for the Tomatoes Speck

To investigate biological control mains against phytopathogenic agent Pseudomonas syringae pv. tomato DC3000, responsible for bacterial speck, tests on the antibacterial activity of six essential oils were carried out. The essential oils, obtained by hydro distillation, was analyzed by gas chromatography (GC). The determination of the antibacterial activity of the essential oils carried out in-vitro using the well diffusion, micro atmosphere methods and the determination of MIC and CMB. Only essential oils of Cedrus atlantica had a negative activity against the bacterial strain. However, the overall results of this study suggested that Mintha pulegium, Thymus vulgaris, Eucalyptus globulus essential oils had potential as a bio-pesticide for the control of bacterial speck disease of tomato.Peer Reviewe

Simulation de trajectoires de gouttes sous des buses à jet plat

Knowledge of physical properties of sprays used in pesticide applications is an important scope because it will allow to improve design and set-up of the machines. Then, better biological efficiency and less bad impact on the environment could be attend. This paper describes two representations of droplet trajectories and velocities under a fan flat nozzle using, the first, a lagrangian approach and, the second, an eulerian approach

The Ciliate Protist Tetrahymena pyriformis as a Cellular Adhesion Model for the Pathogenic Bacterium Staphylococcus aureus

Staphylococcus aureus is one of the main pathogenic agents responsible for nosocomial and community-acquired bacterial infections. The pathogenicity of this Gram-positive bacterium is ensured by its different adhesion factors. Collagen and the extracellular glycoprotein adhesin are among the Staphylococcus most important virulence factors. It has been shown that most of the S. aureus strains carry the ica operon, responsible for biofilm production. However, the coexpression of the icaA and the icaD genes is necessary for complete biofilm synthesis. The aim of our study was to study a collection of 15 clinical strains of S. aureus from different sources for the presence of cna and icaD genes coding intercellular adhesion proteins. We also intended to estimate the strains¿ ability to form biofilms by the red Cong method and to test the adhesion ability of S. aureus to the ciliated protist Tetrahymena pyriformis, which we used as a novel cellular adhesion model. Finally, we checked the adhesion¿s inhibition capacity of some plants extracts. The molecular detection of adhesion genes revealed that 80% of strains are cna positive, and 73% are icaD positive. Qualitative biofilm production of S. aureus revealed that 66.6% of strains were slime producers. The adhesion test revealed that 20% of strains are strongly adhering to T. pyriformis and that the Clematis cirrhosa extract has an anti-adhering effect of S. aureus to the ciliate T. pyriformis.Peer Reviewe

Cell Stress by Phosphate of Two Protozoa Tetrahymena thermophila and Tetrahymena pyriformis

Phosphorus is one of the bioelements most needed as a compound cell by living organisms. Phosphorus is involved in several pathologies: in human with bone and kidney diseases, in mammals with metabolism disorder (glucose, insulin¿¿¿), in microorganisms whose phosphorus is involved in cell growth. Phosphorus has various forms including pyrophosphate, a by-product of multiple pathways of biosynthesis. Enzymes that hydrolyze pyrophosphate are called inorganic pyrophosphatases (PPases). Two major types of inorganic pyrophosphatases are distinguished: the soluble pyrophosphatases (sPPases) and the membrane pyrophosphatases (mPPases or H+/Na+-PPases). They play a key role in the control of intracellular inorganic pyrophosphate level and produce an important ions gradient (H+ or Na+) to the cells. In this work, we primarily focused on the physiological study in a phosphate-poor medium of two models Tetrahymena thermophila and Tetrahymena pyriformis , following the mobility, the growth and the morphology of cells. Secondly, we evaluated the enzymatic activity of soluble and membrane pyrophosphatases in both species grown in the same complex medium. A decrease of cell growth is correlated with unusual morphologies and different mobility in the stress medium. The measurement of soluble and membrane inorganic pyrophosphatases activities also shows a decrease which illustrates the lack of phosphate found in the stress medium. Deficiency of phosphate is a limiting factor for protozoan growth. These results indicate that Tetrahymena can be used as a model of cellular stress and consists of a target to study inorganic pyrophosphatases for a better understanding of phosphate cycle in higher organisms.Peer Reviewe

Inorganic Pyrophosphatases: Study of Interest

Inorganic pyrophosphatases are enzymes that catalyze the hydrolysis of inorganic pyrophosphate to orthophosphate. These enzymes are divided into two groups: the soluble pyrophosphatases and the membrane pyrophosphatases. They vary in structure and each has a determined catalysis mechanism. Soluble pyrophosphatases are ubiquitous enzymes and play a key role in regulating the rate of pyrophosphate and balance in this sense, the biosynthetic reactions. Membrane pyrophosphatases are ion pumps, producing a proton or sodium gradient, and provide critical energy reserves to organisms, especially during stress conditions. Several studies have shown that these enzymes are involved in numerous disorders (diseases, fault cell growth¿¿¿). However they are potential targets for the development of agents against parasites. This article consists of a description of the different types, structures, catalytic properties of inorganic pyrophosphatases and their involvement in cellular metabolism.Peer Reviewe

Cloning and heterologous overexpression of three gap genes encoding different glyceraldehyde-3-phosphate dehydrogenases from the plant pathogenic bacterium Pseudomonas syringae pv. tomato strain DC3000

The gammaproteobacterium Pseudomonas syringae pv. tomato DC3000 is the causal agent of bacterial speck, a common disease of tomato. The mode of infection of this pathogen is not well understood, but according to molecular biological, genomic and proteomic data it produces a number of proteins that may promote infection and draw nutrients from the plant. Glyceraldehyde-3- phosphate dehydrogenase (GAPDH) is a major enzyme of carbon metabolism that was reported to be a surface antigen and virulence factor in other pathogenic microorganisms, but its possible role in the infection process of P. syringae has so far not been studied. Whole-genome sequence analyses revealed the occurrence in this phytopathogenic bacterium of three paralogous gap genes encoding distinct GAPDHs, namely two class I enzymes having different molecular mass subunits and one class III bifunctional D-erythrose-4-phosphate dehydrogenase/GAPDH enzyme. By using genome bioinformatics data, as well as alignments of both DNA and deduced protein sequences, the three gap genes of P. syringae were one-step cloned with a His-Tag in pET21a vector using a PCR-based strategy, and its expression optimized in E. coli BL21 to achieve high yield of the heterologous proteins. In accordance with their distinct molecular phylogenies, these bacterial gap genes encode functional GAPDHs of diverse molecular masses and nicotinamide-coenzyme specificities, suggesting specific metabolic and/or cellular roles.Peer Reviewe