| purine utilization by klebsiella oxytoca m5al: genes for ring-oxidizing and -opening enzymes. | the enterobacterium klebsiella oxytoca uses a variety of inorganic and organic nitrogen sources, including purines, nitrogen-rich compounds that are widespread in the biosphere. we have identified a 23-gene cluster that encodes the enzymes for utilizing purines as the sole nitrogen source. growth and complementation tests with insertion mutants, combined with sequence comparisons, reveal functions for the products of these genes. here, we report our characterization of 12 genes, one encoding gua ... | 2009 | 19060149 |
| genome sequence of klebsiella oxytoca m5al, a promising strain for nitrogen fixation and chemical production. | klebsiella oxytoca is an important microorganism for nitrogen fixation and chemical production. here, we report an annotated draft genome of k. oxytoca strain m5al that contains 5,256 protein-coding genes and 95 structural rnas, which provides a genetic basis for a better understanding of the physiology of this species. | 2013 | 23405358 |
| fermentation of 1,3-propanediol by a lactate deficient mutant of klebsiella oxytoca under microaerobic conditions. | klebsiella oxytoca m5al is an excellent 1,3-propanediol (1,3-pd) producer, but too much lactic acid yielded greatly lessened the fermentation efficiency for 1,3-pd. to counteract the disadvantage, four lactate deficient mutants were obtained by knocking out the ldha gene of lactate dehydrogenase (ldh) of k. oxytoca m5al. the ldh activities of the four mutants were from 3.85 to 6.92% of the parental strain. the fed-batch fermentation of 1,3-pd by mutant ldh3, whose ldh activity is the lowest, was ... | 2007 | 16960737 |
| general nitrogen regulation of nitrate assimilation regulatory gene nasr expression in klebsiella oxytoca m5al. | klebsiella oxytoca can assimilate nitrate and nitrite by using enzymes encoded by the nasfedcba operon. expression of the nasf operon is controlled by general nitrogen regulation (ntr) via the ntrc transcription activator and by pathway-specific nitrate and nitrite induction via the nasr transcription antiterminator. this paper reports our analysis of nasr gene expression. we constructed strains bearing single-copy phi(nasr-lacz) operon fusions within the chromosomal rhabad-rhasr locus. the expr ... | 1999 | 10572131 |
| rna sequence requirements for nasr-mediated, nitrate-responsive transcription antitermination of the klebsiella oxytoca m5al nasf operon leader. | in klebsiella oxytoca, enzymes required for nitrate assimilation are encoded by the nasfedcba operon. nitrate and nitrite induction of nasf operon expression is determined by a transcriptional antitermination mechanism, in which the nasr gene product responds to nitrate or nitrite and overcomes transcription termination at the factor-independent terminator site located in the nasf upstream leader region. previous studies led to the hypothesis that the nasr protein mediates transcription antiterm ... | 1999 | 10493869 |
| nasr, a novel rna-binding protein, mediates nitrate-responsive transcription antitermination of the klebsiella oxytoca m5al nasf operon leader in vitro. | in klebsiella oxytoca (pneumoniae), enzymes required for nitrate assimilation are encoded by the nasfedcba operon. previous genetic studies led to the conclusion that nitrate and nitrite induction of nasf operon expression is determined by a transcriptional antitermination mechanism. in the presence of nitrate or nitrite, the nasr gene product is hypothesized to inhibit transcription termination at the factor-independent terminator site located in the nasf operon leader region. to test this mode ... | 1998 | 9769209 |