Project description:Here we performed a comprehensive genomic and proteomics analysis of P. stutzeri in aerobic and oxygen-limiting conditions. We combined de novo genome assembly relying on 3rd generation long read sequencing technologies to report the first complete P. stutzeri ATCC14405 genome, which added over 110 kb of sequence and contains 126 full length CDS that were only partially covered in the fragmented short read-based genome assembly available for this strain. With this optimal basis for downstream functional genomics, we next carried out state of the art bottom-up and top-down proteomics analyses to report the most detailed study of proteome remodeling in response to oxygen limitation in P. stutzeri. We identified more than 2900 proteins, i.e. greater than 70% of the theoretical proteome, including 160 annotated small proteins. The proteins included well-established enzymes involved in denitrification and metabolic adaptation to oxygen-limiting conditions, as well as uncharacterized proteins. Notably, we identified 16 novel small proteins that had so far been missed in the genome annotation.
Project description:Cysteine is an amino acid containing sulfhydryl (-SH) group which is the basis of cysteine involved in sulfur metabolism and heavy metal detoxification in microorganisms. Here, we demonstrate that adding L-cysteine significantly improves the cadmium resistance and removal ability of Pseudomonas stutzeri 273. Threonine dehydratase (TSD) connects L-cysteine metabolism and cadmium resistance through CdS nanoparticle biomineralization with the ability of catalyzing L-cysteine desulfuration and H2S generation in P. stutzeri 273. Gene knockout of TSD in P. stutzeri 273 results in the decrease of L-cysteine and cadmium resistance, decline of H2S generation, and reduction of CdS biosynthesis ability.
Project description:A whole genome DNA microarray was used to undertake a global transcriptional analysis of nitrogen fixation and ammonium repression in Pseudomonas stutzeri A1501. The aim of this study was to identify the genes that are up-regulated under nitrogen fixation conditions and rapidly down-regulated as soon as 10 min after ammonia shock. The expression changed genes may be the candidate genes for the ammonia signal transmission or be involved in the nitrogen regulatory mechanism.
Project description:A whole genome DNA microarray was used to undertake a global transcriptional analysis of nitrogen fixation and ammonium repression in Pseudomonas stutzeri A1501. The aim of this study was to identify the genes that are up-regulated under nitrogen fixation conditions and rapidly down-regulated as soon as 10 min after ammonia shock. The expression changed genes may be the candidate genes for the ammonia signal transmission or be involved in the nitrogen regulatory mechanism. First, P. stutzeri A1501 was treated with 0.1 mM ammonia and 0.5% Oxygen tension until the nitrogenase activity was detectable. Then the cells were sudden shifted from the nitrogen fixation conditions to the ammonia repression conditions by addition of 20 mM ammonia for 10min. Subsequently, the bacterium was collected and began the RNA extraction process. Thus, we compare the expression profilings in these two conditions in order to identify the candidate genes.
