Common patterns – unique features: nitrogen metabolism and regulation in Gram-positive bacteria

Amon, Johannes; Titgemeyer, Fritz; Burkovski, Andreas

doi:10.1111/j.1574-6976.2010.00216.x

Cited by 76 publications

(67 citation statements)

References 158 publications

(231 reference statements)

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“…Phosphorylation of the response regulator NtrC by the NtrB kinase is controlled by the nitrogen regulatory protein PII (GlnB) mainly depending on the cellular glutamine concentration (via uridylylation/deuridylylation of PII by the uridylyltransferase GlnD). In B. subtilis, GlnR, TnrA and GltC (Schreier et al, 1989;Wray et al, 1996Wray et al, , 1998Picossi et al, 2007) co-operate to regulate nitrogen metabolism (for review, see Fisher, 1999;Sonenshein, 2007;Amon et al, 2010). GlnR is active during growth with excess nitrogen, where it represses the expression of glnRA, ureABC and tnrA (for review, see Sonenshein, 2007;Amon et al, 2010), whereas TnrA is active during nitrogen-limited growth, where it activates and represses the expression of genes involved in the transport and metabolism of nitrogen compounds.…”

Section: Introductionmentioning

confidence: 99%

l-Glutamine as a nitrogen source for Corynebacterium glutamicum: derepression of the AmtR regulon and implications for nitrogen sensing

et al. 2010

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Corynebacterium glutamicum, a Gram-positive soil bacterium employed in the industrial production of various amino acids, is able to use a number of different nitrogen sources, such as ammonium, urea or creatinine. This study shows that l-glutamine serves as an excellent nitrogen source for C. glutamicum and allows similar growth rates in glucose minimal medium to those in ammonium. A transcriptome comparison revealed that the nitrogen starvation response was elicited when glutamine served as the sole nitrogen source, meaning that the target genes of the global nitrogen regulator AmtR were derepressed. Subsequent growth experiments with a variety of mutants defective in nitrogen metabolism showed that glutamate synthase is crucial for glutamine utilization, while a putative glutaminase is dispensable under the experimental conditions used. The gltBD operon encoding the glutamate synthase is a member of the AmtR regulon. The observation that the nitrogen starvation response was elicited at high intracellular l-glutamine levels has implications for nitrogen sensing. In contrast with other Gram-positive and Gram-negative bacteria such as Bacillus subtilis, Salmonella enterica serovar Typhimurium and Klebsiella pneumoniae, a drop in glutamine concentration obviously does not serve as a nitrogen starvation signal in C. glutamicum.

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Section: Introductionmentioning

confidence: 99%

l-Glutamine as a nitrogen source for Corynebacterium glutamicum: derepression of the AmtR regulon and implications for nitrogen sensing

et al. 2010

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“…GDH plays a significant role in the metabolism of nitrogen in many organisms by assimilating ammonia through the conversion of 2-oxoglutarate to glutamate. In the enteric proteobacteria, such as Escherichia coli and Salmonella, GDH is the primary nitrogen assimilation pathway when ammonia is in excess (Ͼ1 mM), though with Bacillus subtilis and many Gram-positive bacteria, GDH activity is absent, as excess ammonia is rarely encountered (6,7). The lowaffinity GDH reaction is energy independent but redox dependent, using NAD(P)H as a cofactor.…”

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Nitrogen Utilization and Metabolism in Ruminococcus albus 8

Kim

Henriksen

Cann

et al. 2014

Appl Environ Microbiol

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The model rumen Firmicutes organism Ruminococcus albus 8 was grown using ammonia, urea, or peptides as the sole nitrogen source; growth was not observed with amino acids as the sole nitrogen source. Growth of R. albus 8 on ammonia and urea showed the same growth rate (0.08 h ؊1 ) and similar maximum cell densities (for ammonia, the optical density at 600 nm [OD 600 ] was 1.01; and for urea, the OD 600 was 0.99); however, growth on peptides resulted in a nearly identical growth rate (0.09 h ؊1 ) and a lower maximum cell density (OD 600 ‫؍‬ 0.58). To identify differences in gene expression and enzyme activities, the transcript abundances of 10 different genes involved in nitrogen metabolism and specific enzyme activities were analyzed by harvesting mRNA and crude protein from cells at the mid-and late exponential phases of growth on the different N sources. Transcript abundances and enzyme activities varied according to nitrogen source, ammonia concentration, and growth phase. Growth of R. albus 8 on ammonia and urea was similar, with the only observed difference being an increase in urease transcript abundance and enzyme activity in urea-grown cultures. Growth of R. albus 8 on peptides showed a different nitrogen metabolism pattern, with higher gene transcript abundance levels of gdhA, glnA, gltB, amtB, glnK, and ureC, as well as higher activities of glutamate dehydrogenase and urease. These results demonstrate that ammonia, urea, and peptides can all serve as nitrogen sources for R. albus and that nitrogen metabolism genes and enzyme activities of R. albus 8 are regulated by nitrogen source and the level of ammonia in the growth medium.A mmonia is the major end product of digestion of dietary protein and nonprotein nitrogen (urea and amino acids), as well as the major source of nitrogen for protein synthesis by ruminal bacteria (1-3). Results over a wide range of feed and N intakes demonstrate that 60 to 80% of bacterial N is derived from ammonia as a precursor (4). Since 14% of cell dry mass is nitrogen, bacterial protein synthesis and growth are greatly affected by the efficiency of ammonia assimilation. Despite its importance and central role as an intermediate in the degradation as well as assimilation of dietary nitrogen by intestinal bacteria, our understanding of the mechanism of ammonia assimilation in ruminal bacteria is superficial.Enzymes for assimilation of ammonia are widely conserved across the bacterial domain, with differences in distribution and transcriptional regulation influenced by environmental niche. Glutamate dehydrogenase (GDH), glutamine synthetase (GS), and glutamate synthase (GOGAT) are the three major types of enzymes that regulate the intracellular pool of nitrogen by controlling ammonia assimilation (5). GDH plays a significant role in the metabolism of nitrogen in many organisms by assimilating ammonia through the conversion of 2-oxoglutarate to glutamate. In the enteric proteobacteria, such as Escherichia coli and Salmonella, GDH is the primary nitrogen assimilation pathway when ...

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“…Nitrogen control of metabolism in several Actinomycetes species is mediated by a response regulator, GlnR, belonging to the OmpR family (10,18). The GlnR-mediated transcription regulatory network that coordinates the control of expression of genes involved in nitrogen assimilation, nitrogen metabolism, and other metabolic activity has been explored in Streptomyces coelicolor (19,20) and Streptomyces venezuelae (21).…”

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Reciprocal Regulation of GlnR and PhoP in Response to Nitrogen and Phosphate Limitations in Saccharopolyspora erythraea

Yao

2016

Appl Environ Microbiol

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Nitrogen and phosphate source sensing, uptake, and assimilation are essential for the growth and development of microorganisms. In this study, we demonstrated that SACE_6965 encodes the phosphate regulator PhoP, which controls the transcription of genes involved in phosphate metabolism in the erythromycin-producing Saccharopolyspora erythraea. We found that PhoP and the nitrogen regulator GlnR both regulate the transcription of glnR as well as other nitrogen metabolism-related genes. Interestingly, both GlnR-and PhoP-binding sites were identified in the phoP promoter region. Unlike the nonreciprocal regulation of GlnR and PhoP observed in Streptomyces coelicolor and Streptomyces lividans, GlnR negatively controls the transcription of the phoP gene in S. erythraea. This suggests that GlnR directly affects phosphate metabolism and demonstrates that the cross talk between GlnR and PhoP is reciprocal. Although GlnR and PhoP sites in the glnR and phoP promoter regions are located in close proximity to one another (separated by only 2 to 4 bp), the binding of both regulators to their respective region was independent and noninterfering. These results indicate that two regulators could separately bind to their respective binding sites and control nitrogen and phosphate metabolism in response to environmental changes. The reciprocal cross talk observed between GlnR and PhoP serves as a foundation for understanding the regulation of complex primary and secondary metabolism in antibiotic-producing actinomycetes.

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Common patterns – unique features: nitrogen metabolism and regulation in Gram-positive bacteria

Cited by 76 publications

References 158 publications

l-Glutamine as a nitrogen source for Corynebacterium glutamicum: derepression of the AmtR regulon and implications for nitrogen sensing

l-Glutamine as a nitrogen source for Corynebacterium glutamicum: derepression of the AmtR regulon and implications for nitrogen sensing

Nitrogen Utilization and Metabolism in Ruminococcus albus 8

Reciprocal Regulation of GlnR and PhoP in Response to Nitrogen and Phosphate Limitations in Saccharopolyspora erythraea

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