379 research outputs found
A Short Description of a Translator-Writing System (BOBS-System)
The paper itself is an abstract describing a translator-writing-system called the BOBS-System, which is an implementation of some of the ideas in the Ph. D. thesis of De Remer. This thesis describes closely the parsing techniques for the hierarchy of LR(k)-grammars. The main parts of the BOBS-System is described without many details
Nitrogen regulation of the <i>xyl</i> genes of <i>Pseudomonas putida</i> mt-2 propagates into a significant effect of nitrate on <i>m</i>-xylene mineralization in soil
The nitrogen species available in the growth medium are key factors determining expression of xyl genes for biodegradation of aromatic compounds by Pseudomonas putida. Nitrogen compounds are frequently amended to promote degradation at polluted sites, but it remains unknown how regulation observed in the test tube is propagated into actual catabolism of, e.g. mâxylene in soil, the natural habitat of this bacterium. To address this issue, we have developed a testâtubeâtoâsoil model system that exposes the endâeffects of remediation practices influencing gene expression of P. putida mtâ2. We found that NO (3) (â) compared with NH (4) (+) had a stimulating effect on xyl gene expression in pure culture as well as in soil, and that this stimulation was translated into increased mâxylene mineralization in soil. Furthermore, expression analysis of the nitrogenâregulated genes amtB and gdhA allowed us to monitor nitrogen sensing status in both experimental systems. Hence, for nitrogen sources, regulatory patterns that emerge in soil reflect those observed in liquid cultures. The current study shows how distinct regulatory traits can lead to discrete environmental consequences; and it underpins that attempts to improve bioremediation by nitrogen amendment should integrate knowledge on their effects on growth and on catabolic gene regulation under natural conditions
- âŚ