Characterization of a synthetic bacterial self-destruction device for programmed cell death and for recombinant proteins release

<p>Abstract</p> <p>Background</p> <p>Bacterial cell lysis is a widely studied mechanism that can be achieved through the intracellular expression of phage native lytic proteins. This mechanism can be exploited for programmed cell death and for gentle cell disruption to release recombinant proteins when <it>in vivo </it>secretion is not feasible. Several genetic parts for cell lysis have been developed and their quantitative characterization is an essential step to enable the engineering of synthetic lytic systems with predictable behavior.</p> <p>Results</p> <p>Here, a BioBrick™ lysis device present in the Registry of Standard Biological Parts has been quantitatively characterized. Its activity has been measured in <it>E. coli </it>by assembling the device under the control of a well characterized N-3-oxohexanoyl-L-homoserine lactone (HSL) -inducible promoter and the transfer function, lysis dynamics, protein release capability and genotypic and phenotypic stability of the device have been evaluated. Finally, its modularity was tested by assembling the device to a different inducible promoter, which can be triggered by heat induction.</p> <p>Conclusions</p> <p>The studied device is suitable for recombinant protein release as 96% of the total amount of the intracellular proteins was successfully released into the medium. Furthermore, it has been shown that the device can be assembled to different input devices to trigger cell lysis in response to a user-defined signal. For this reason, this lysis device can be a useful tool for the rational design and construction of complex synthetic biological systems composed by biological parts with known and well characterized function. Conversely, the onset of mutants makes this device unsuitable for the programmed cell death of a bacterial population.</p

Estudio de la diversidad del hongo responsable de la piriculariosis del arroz, y su aplicación

Magnaporthe oryzae es responsable de la enfermedad mas importante del arroz en Europa. En este trabajo se recogieron 987 aislados de este hongo en siete países europeos productores de arroz, y se investigó su diversidad genética con 11 marcadores microsatélite. Los genotipos multilocus (MLGs) más frecuentes son comunes a los países europeos. Sin embargo, algunos son específicos de los distintos países, o incluso de determinadas áreas de cultivo. La diversidad genotípica media en los campos de cultivo revela que, a pesar de que hay uno o dos genotipos dominantes, frecuentemente coexisten varios genotipos. La hipótesis del arroz rojo como una fuente de inóculo primario no se puede excluir. La evolución genética de M.oryzae se ha investigado en dos de estos países en los últimos 25 años: en Francia se han observado cambios significativos de la población con el tiempo, al contrario que en ltalia. Estos datos muestran que hay un importante flujo de genes entre las zonas arroceras europeas, probablemente a través del transporte de semillas infectadas. También muestran evidencias de diferenciación en una escala geográfica muy pequeña, lo que sugiere una adaptación local