Stickstoffregulation bei Mikroorganismen

Huth, J.; Liebs, P.

doi:10.1016/s0232-4393(88)80038-6

Cited by 9 publications

(4 citation statements)

References 69 publications

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“…Nitrogen starvation leads to GS-GOGAT mediated glutamine synthesis, whereas high ammonia availability leads to the activation of GDH 3 , 4 . The pathways involved in ammonia assimilation are common among bacteria, cyanobacteria, algae, yeasts, and fungi 5 . In Helicobacter pylori , ammonia is produced by urease, which exhibits higher activity compared with that in other species, and is used in the neutralization of gastric acid for survival in animal hosts 6 .…”

Section: Introductionmentioning

confidence: 99%

Structural Analysis of Glutamine Synthetase from Helicobacter pylori

Joo

Park

Jang

et al. 2018

Sci Rep

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Glutamine synthetase (GS) is an enzyme that regulates nitrogen metabolism and synthesizes glutamine via glutamate, ATP, and ammonia. GS is a homo-oligomeric protein of eight, ten, or twelve subunits, and each subunit-subunit interface has its own active site. GS can be divided into GS I, GS II, and GS III. GS I and GS III form dodecamer in bacteria and archaea, whereas GS II form decamer in eukaryotes. GS I can be further subdivided into GS I-α and GS I-β according to its sequence and regulatory mechanism. GS is an essential protein for the survival of Helicobacter pylori which its infection could promote gastroduodenal diseases. Here, we determined the crystal structures of the GS from H. pylori (Hpy GS) in its apo- and substrate-bound forms at 2.8 Å and 2.9 Å resolution, respectively. Hpy GS formed a dodecamer composed of two hexameric rings stacked face-to-face. Hpy GS, which belongs to GS I, cannot be clearly classified as either GS I-α or GS I-β based on its sequence and regulatory mechanism. In this study, we propose that Hpy GS could be classified as a new GS-I subfamily and provide structural information on the apo- and substrate-bound forms of the protein.

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Section: Introductionmentioning

confidence: 99%

Structural Analysis of Glutamine Synthetase from Helicobacter pylori

Joo

Park

Jang

et al. 2018

Sci Rep

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“…In some microorganisms, including yeast, a change in extracellular pH is correlated with ammonium assimilation [45]. Thus, we used MM liquid culture with ammonium to monitor the biomass of Guy11 and Δ Moglk1 mutants over a period of 7 days.…”

Section: Resultsmentioning

confidence: 99%

“…In S. cerevisiae , the pH of the culture can be used as a simple and effective control parameter for biomass-related products [44] . In some microorganisms, including yeast, a change in extracellular pH is correlated with ammonium assimilation [45] . Thus, we used MM liquid culture with ammonium to monitor the biomass of Guy11 and Δ Moglk1 mutants over a period of 7 days.…”

Section: Resultsmentioning

confidence: 99%

The Function of MoGlk1 in Integration of Glucose and Ammonium Utilization in Magnaporthe oryzae

Zhang

Dou

et al. 2011

PLoS ONE

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Hexokinases are conserved proteins functioning in glucose sensing and signaling. The rice blast fungus Magnaporthe oryzae contains several hexokinases, including MoHxk1 (hexokinase) and MoGlk1 (glucokinase) encoded respectively by MoHXK1 and MoGLK1 genes. The heterologous expression of MoGlk1 and MoHxk1 in Saccharomyces cerevisiae confirmed their conserved functions. Disruption of MoHXK1 resulted in growth reduction in medium containing fructose as the sole carbon source, whereas disruption of MoGLK1 did not cause the similar defect. However, the ΔMoglk1 mutant displayed decreased proton extrusion and a lower biomass in the presence of ammonium, suggesting a decline in the utilization of ammonium. Additionally, the MoGLK1 allele lacking catalytic activity restored growth to the ΔMoglk1 mutant. Moreover, the expression of MoPMA1 encoding a plasma membrane H+-ATPase decreased in the ΔMoglk1 mutant that can be suppressed by glucose and G-6-P. Thus, MoGlk1, but not MoHxk1, regulates ammonium utilization through a mechanism that is independent from its catalytic activity.

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“…Alternatively, microorganisms may carry out assimilatory nitrate reduction, which is used to incorporate nitrogen into biomolecules (Larose et al, 2013a;Richardson and Watmough, 1999). The assimilatory process is performed by a range of microorganisms including bacteria, algae, yeasts, and fungi (Huth and Liebs, 1988). Thus, further studies on eukaryotes, including algae, may provide a full understanding of the nitrogen consumption mechanisms in subsurface snow.…”

Section: Distinct Nitrogen-transformation Processes In Surface and Su...mentioning

confidence: 99%

Temporal variation of bacterial community and nutrients in Tibetan glacier snowpack

Chen

Liu

et al. 2022

The Cryosphere

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Abstract. The Tibetan Plateau harbors the largest number of glaciers outside the polar regions, which are the source of several major rivers in Asia. These glaciers are also major sources of nutrients for downstream ecosystems, while there is a little amount of data available on the nutrient transformation processes on the glacier surface. Here, we monitored the carbon and nitrogen concentration changes in a snowpit following a snowfall in the Dunde Glacier of the Tibetan Plateau. The association of carbon and nitrogen changes with bacterial community dynamics was investigated in the surface and subsurface snow (depth at 0–15 and 15–30 cm, respectively) during a 9 d period. Our results revealed rapid temporal changes in nitrogen (including nitrate and ammonium) and bacterial communities in both surface and subsurface snow. Nitrate and ammonium concentrations increased from 0.44 to 1.15 mg L−1 and 0.18 to 0.24 mg L−1 in the surface snow and decreased from 3.81 to 1.04 and 0.53 to 0.25 mg L−1 in the subsurface snow over time. Therefore, we suggest that the surface snow is not nitrogen-limited, while the subsurface snow is associated with nitrogen consumption processes and is nitrogen-limited. The nitrate concentration co-varied with bacterial diversity, community structure, and the predicted nitrogen fixation and nitrogen assimilation/denitrification-related genes (narG), suggesting nitrogen could mediate bacterial community changes. The nitrogen limitation and enriched denitrification-related genes in subsurface snow suggested stronger environmental and biotic filtering than those in surface snow, which may explain the lower bacterial diversity, more pronounced community temporal changes, and stronger biotic interactions. Collectively, these findings advance our understanding of bacterial community variations and bacterial interactions after snow deposition and provide a possible biological explanation for nitrogen dynamics in snow.

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Stickstoffregulation bei Mikroorganismen

Cited by 9 publications

References 69 publications

Structural Analysis of Glutamine Synthetase from Helicobacter pylori

Structural Analysis of Glutamine Synthetase from Helicobacter pylori

The Function of MoGlk1 in Integration of Glucose and Ammonium Utilization in Magnaporthe oryzae

Temporal variation of bacterial community and nutrients in Tibetan glacier snowpack

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