Método de la microgota: usado con agar cromogénico es un procedimiento útil para el monitoreo sanitario en acuicultura

Indexación: Web of Science, Scielo.The microdot method is a downscaling methodology of traditional tenfold serial dilution procedure used in microbiology. The microdot method uses 100 mu L for serial dilution and count colonies in a spot of 10 mu L. In this study we counted colonies directly in a chromogenic agar plate to determine, at the same time, the presence and cell concentration of target bacteria required for sanitary monitoring of Chilean export fishery products. Due to among importers countries the most concerning bacteria included in sanitary monitoring are Escherichia coli, Listeria monocytogenes and Staphylococcus aureus, we used the chromogenic agar; CHROMagar ECC, CHROMagar Listeria and Baird Parker agar, respectively. The results shows no differences between quantitative results obtained with microdot and traditional method during the quantification of a culture of Escherichia coli (1.5 L). The sensitivity and specificity of the microdot method in association with each chromogenic agar was demonstrated in vitro with reference strains. In addition, the usefulness in sanitary monitoring of aquaculture procedures was evaluated in Artemia salina tanks. This method did not detected sanitary problems in surface water. Although other colonies grown in the chromogenic agar plate, their morphological and chromogenic properties not correspond to Escherichia coli, Listeria monocytogenes and Staphylococcus aureus, being identified as Salmonella enterica subsp. enterica, Microbacterium sp., Bacillus sp. and Staphylococcus pasteuri by 16S rRNA gene sequence analysis. Hence, we propose the microdot chromogenic method as a low cost, specific and reliable procedure for sanitary monitoring of aquaculture procedures.El método de la microgota es una versión a menor escala del procedimiento tradicional de dilución en serie en base diez utilizados en microbiología. El método realiza diluciones en 100 µL y cuenta colonias crecidas en una gota de 10 µL. En este estudio se cuentan colonias directamente en placas cromogénicas para determinar densidad celular y presencia de bacterias requeridas en vigilancia sanitaria de productos pesqueros chilenos de exportación. Entre los requisitos de países importadores, la vigilancia sanitaria involucra frecuentemente a Escherichia coli, Listeria monocytogenes y Staphylococcus aureus, por lo que se utilizan los agares cromogénicos; CHROMagar ECC, CHROMagar Listeria y agar Baird Parker para su identificación. La comparación entre el método de microgota y el método tradicional no muestra diferencias al evaluar un cultivo de Escherichia coli (1,5 L). La sensibilidad y especificidad del método de microgota junto a cada agar cromogénico se demostró in vitro con cepas de referencia. Además, en estanques de Artemia salina se evaluó la utilidad de este método para el monitoreo sanitario. Este método no mostró problemas sanitarios en aguas superficiales, aunque otras colonias crecieron en la placa de agar cromogénico. Sus propiedades morfológicas y cromogénicas no corresponden a Escherichia coli, Listeria monocytogenes y Staphylococcus aureus, siendo identificadas según el análisis de la secuencia del gen 16S rRNA como Salmonella enterica subsp. enterica, Microbacterium sp., Bacillus sp. y Staphylococcus pasteuri. Por lo tanto, se propone el método de microgota cromogénico como un procedimiento de bajo costo, específico y fiable para el monitoreo sanitario en acuicultura.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2016000400009&lng=e

SMAC dependency of XIAP mediated chemoresistance

An important hallmark of tumor cells is their resistance to apoptosis. Apoptosis is a tightly regulated cellular response that ultimately results in the elimination and disposal of unwanted or damaged cells. Apoptosis is brought about by a family of proteases known as the caspases, the activity of which is responsible for the organized destruction of the cell. Each step of the apoptotic signaling cascade is under stringent control. Apoptotic signaling can be regulated at the apical point of the apoptotic cascade by controlling the translation of death-inducing signals into proteolytic activity or more critically by direct modulation of proteolytic activity of caspases. The later is modulated by direct interaction of caspases with members of the inhibitor of apoptosis protein (IAP) family, the most studied one, X-linked IAP (XIAP), has evolved to potently inhibit the enzymatic activity of mammalian caspases. By efficiently inhibiting caspases XIAP has been shown to block apoptosis and described as a factor conferring resistance against different chemotherapeutic drugs (chemoresistant factor) in a variety of tumor cells. Furthermore, elevated XIAP expression has been frequently observed in several tumor tissues and XIAP targeting sensitizes diverse tumor cell lines for chemotherapeutic agents underlining the role of XIAP in tumor chemoresistance. However, by generating stable cell lines overexpressing XIAP the data provided show that XIAP overexpression alone does not generate a chemoresistant phenotype. Experiments evaluating both XIAP overexpression and stable knock-down of SMAC, a critical regulator of XIAP, show that XIAP action as a chemoresistant factor is tightly controlled by SMAC. In contrast to Bcl2 that acts as a mitochondrial gatekeeper, XIAP does not alter mitochondrial functions. Cytostatic drugs readily induce release of SMAC in cells with functionally intact mitochondria independent of caspase action, thereby completely neutralizing the anti-apoptotic action of even overexpressed XIAP. Although increased cytotoxic activity by different cytostatic drugs was observed, XIAP targeting failed to restore chemosensitivity in chemoresistant Hodgkin Lymphoma-derived cell lines indicating limited involvement of XIAP in chemoresistance. Unlike chemotherapeutic agents, XIAP targeting resulted in complete reactivation of the apoptotic machinery in response to grzB treatment regardless of mitochondrial functional state. These data demonstrated for the first time that it is essential to assess the mitochondrial capacity to release SMAC as well as the expression levels of both XIAP and SMAC in order to predict the chemosensitivity of particular tumours, a relationship that has not previously been recognised

Development of a strategic and tactical game plan for junior mining companies

ABSTRACT This thesis undertakes to present a game plan for junior mining companies. It culminates with a game plan model that incorporates all the key steps and tasks that mining investors and entrepreneurs need to use to establish globally competitive junior mining companies. It is based on the research of several listed junior mining companies. The game of junior mining is defined by rules, the player, the elements of playing, and the definitions of winning and scoring. The rules of the game are those defined by the resources industry and general business concepts. The mining assets around which the junior mining game is played are exploration projects, feasibility studies, mine development projects or operating mines. The player is the junior mining company intent on winning the game. Playing the game is done through executing the steps, tasks and simple models and matrices associated with the four business pillars: strategy development, legal and financial, operations management and risks management. The first pillar is strategic, while the last three pillars are tactical. For each business pillar, databases were developed, for the purposes of creating references and benchmarks for the game plan. The databases have been created from the analysis of twenty randomly selected junior mining companies, the author’s practical experiences and previous research. Scoring the game is undertaken by completing the game score matrix, which scores the mining assets, the business pillars and the financial performance, and provides an overall company score. The total company score highlights the strengths and weaknesses of the company. Undertaking the process of playing the game iteratively will lead to creating a globally competitive junior mining company. Winning the game is defined as creating a sustainable junior mining company, that grows to a mid-tier company, or is bought out by a major mining company. ii In the thesis, the game is played using the hypothetical case study of a of a coal junior mining company, with a marginal coal mine, an attractive feasibility study and an exploration project. Step by step the game is played leading to a company score and exposing the company’s strengths and weaknesses. The research concludes by presenting a holistic game plan model that can be applied to any junior mining company in any commodity in constantly changing resources industry dynamics