Anaerobic growth and potential for amino acid production by nitrate respiration in Corynebacterium glutamicum
85
Citation
64
Reference
10
Related Paper
Citation Trend
Keywords:
Corynebacterium glutamicum
Anaerobic respiration
Total activities of nitrate and nitrite reductases were higher in 4 to 20 day old maize plants in the leaves than in the roots. The ratio of activities found in the leaves and in the roots respectively was much higher in the case of nitrate reductase than in the case of nitrite reductase. On the other hand higher glutamate dehydrogenase activity in the roots than in the leaves clearly indicates that the roots play a more important role in the assimilation of ammonium than in the assimilation of nitrate. When comparing the distribution of seminal and nodal adventitious roots of maize seedlings with the assimilation of inorganic nitrogen on the basis of enzyme levels, it could be deduced that during the first 20 days of seedling growth seminal roots were more involved in the assimilation of nitrate whereas nodal adventitious roots were more active in ammonium assimilation.
Nitrogen Assimilation
Assimilation (phonology)
Glutamate synthase
Cite
Citations (4)
The activities of the enzymes nitrate reductase (EC 1.6.6.1) and nitrite reductase (EC 1.7.99.3) were measured in the leaves and roots of whole plants of Catharanthus roseus grown in different nitrogen sources: water (control), 20 mM KNO 3 , 2 mM NH 4 Cl, and a mixture of nitrate and ammonium. The activities of these enzymes were also measured in leaf explants incubated in the same nitrogen sources. The results indicate that nitrate reductase and nitrite reductase in leaves behaved very differently from those in roots. Activity of leaf nitrate reductase measured in vitro decreased with nitrate and increased with ammonium, while in the root, it only decreased when the mixture of both nitrogen sources was employed. In contrast, nitrite reductase from roots was modified by the nitrogen source while the enzyme from the leaves was not. The amino acid pool was increased by all of the nitrogen sources in both whole plants and explants.
Catharanthus roseus
Nitrogen Cycle
Cite
Citations (0)
Nitrite reduction, catalyzed by nitrite reductase, is a key step in the denitrification pathway because it catalyzes the reduction of soluble nitrite (NO2-) into nitric oxide gas (NO). The production of nitric oxide gas therefore decreases the amount of nitrogen in soils. Other studies have investigated the effect of oxygen on denitrification in a few specific microorganisms (e.g. Aquaspirillum magnetotacticum, Thiosphaera pantotropha, and Paracoccus denitrificans). In this study, we tested the effect of oxygen on nitrite reduction in seven strains representing 5 different genera obtained from Tallgrass Prairie soil. The strains were chosen based on positive detection of at least one functional gene in the denitrification pathway along with positive results for nitrate (NO3-) and/or nitrite reduction after growth in nitrate broth in a microtiter plate assay. Under these conditions which did not totally exclude oxygen, three strains were able to reduce nitrite while four strains did not reduce nitrite. All seven strains were retested for the production/consumption of nitrite under strictly anaerobic conditions using nitrate as the electron acceptor. In addition, the strains were screened for genes encoding the copper nitrite reductase (nirK) and the cytochrome cd1-nitrite reductase (nirS) and other functional markers of denitrification pathway, namely nitric oxide reductase gene (norB) and nitrous oxide (N2O) reductase gene (nosZ) by PCR amplification using specific primers. Our results show that under strict anaerobic conditions, two additional strains demonstrated nitrite reduction. Although none of the molecular markers showed perfect correlation with the ability to reduce nitrite, nirS/nirK, commonly used to screen environmental samples for denitrifying bacteria, was detected in only two of the five strains shown in this study to reduce nitrite. More nitrite reducing strains were correctly identified when both the cnorB and nosZ primer sets were used. ©2015 Oklahoma Academy of Science
Paracoccus denitrificans
Nitrous-oxide reductase
Aerobic denitrification
Cite
Citations (1)
Maize (Zea mays L. cv. Golden Cross Bantam T51) seedlings were grown in a greenhouse at near optimal temperature (30/25°C) with seven levels of nitrate (0.4 to 12 mM). The activity of nitrate reductase, nitrite reductase, glutamine synthetase, GOGAT, and NADH-glutamate dehydrogenase in leaf tissues expressed on a fresh weight basis increased with increasing N except in the case of NADH-glutamate dehydrogenase where the activity continued to decrease. When the activity was expressed on a unit of soluble protein basis it was possible to classify these enzymes into three groups based on their response to the nitrate supplied. The activities of GOGAT in addition to nitrate reductase as the first group increased logarithmically with increasing nitrate application, in showing a concentration lag. Glutamine synthetase and nitrite reductase as the second group responded poorly to changes in the nitrate level. In contrast, the activity of NADH-glutamate dehydrogenase as the third group decreased exponentially with increasing N application. Correlation between leaf biomass induced by differences in the nitrate levels and enzyme activity was highly positive for nitrate reductase, glutamine synthetase, and GOGAT but highly negative for NADH-glutamate dehydrogenase. No significant correlation was found between the nitrite reductase activity and leaf biomass. The enhancement of the glutamine synthetase activity by the increase of N application expressed on a chlorophyll or packed volume basis was greater in bundle sheath strands than in mesophyll protoplasts.
Glutamate synthase
Nitrogen Assimilation
Cite
Citations (4)
Plants take up nitrogen in the form of nitrate and ammonia through nitrate assimilation pathway.Nitrate assimilation is highly regulated process by two successive enzymes,nitrate reductase (NR) and nitrite reductase (NiR),which mainly controll the primary nitrogen assimilation.In higher plants,various external and endogenous factors influence the regulation of NR and NiR gene expression transcriptionally as well as post-transcriptionally.Post-translational modulation is an important mechanism to eliminate the accumulation of nitrite.Development of molecular biology methods will contribute to the research of regulatory networks of NR and NiR by creating mutants and transgenic lines.
Nitrogen Assimilation
Assimilation (phonology)
Cite
Citations (8)
Soybean (Glycine max L. cv Williams) seeds were sown in pots containing a 1:1 perlite-vermiculite mixture and grown under greenhouse conditions. Nodules were initiated with a nitrate reductase expressing strain of Rhizobium japonicum, USDA 110, or with nitrate reductase nonexpressing mutants (NR− 108, NR− 303) derived from USDA 110. Nodules initiated with either type of strain were normal in appearance and demonstrated nitrogenase activity (acetylene reduction). The in vivo nitrate reductase activity of N2-grown nodules initiated with nitrate reductase-negative mutant strains was less than 10% of the activity shown by nodules initiated with the wild-type strain. Regardless of the bacterial strain used for inoculation, the nodule cytosol and the cell-free extracts of the leaves contained both nitrate reductase and nitrite reductase activities. The wild-type bacteroids contained nitrate reductase but not nitrite reductase activity while the bacteroids of strains NR− 108 and NR− 303 contained neither nitrate reductase nor nitrite reductase activities. Addition of 20 millimolar KNO3 to bacteroids of the wild-type strain caused a decrease in nitrogenase activity by more than 50%, but the nitrate reductase-negative strains were insensitive to nitrate. The nitrogenase activity of detached nodules initiated with the nitrate reductase-negative mutant strains was less affected by the KNO3 treatment as compared to the wild-type strain; however, the results were less conclusive than those obtained with the isolated bacteroids. The addition of either KNO3 or KNO2 to detached nodules (wild type) suspended in a semisolid agar nutrient medium caused an inhibition of nitrogenase activity of 50% and 65% as compared to the minus N controls, and provided direct evidence for a localized effect of nitrate and nitrite at the nodule level. Addition of 0.1 millimolar sucrose stimulated nitrogenase activity in the presence or absence of nitrate or nitrite. The sucrose treatment also helped to decrease the level of nitrite accumulated within the nodules.
Bradyrhizobium japonicum
Cite
Citations (81)
Abstract Nitrite utilization by the roots of kidney bean, corn, and sunflower plants was investigated using 15N-labeled nitrite, and the following were concluded. (1) The primary roots of the corn plant assimilate nitrite to amino acids by a combination of nitrite reductase, glutamine synthetase and glutamate synthase. The reduction rate is rapid in the apical zone compared to the rates in the more mature zones. (2) Nitrite reduction to amino level occurs rapidly in the roots of 20-day-old seedlings of the three plants at similar rates in the daytime and in the night. This reduction seems to be more rapid than the reduction of nitrate to amino level. (3) The nitrogen derived from fed nitrogen was transferred from the root to the leaf more actively in the daytime than in the night. This trend was true for both the nitrite-fed and nitrate-fed plants. However, nitrite does not seem to be transferred to the leaf, but some nitrate may be transferred in an unchanged form.
Glutamate synthase
Cite
Citations (12)
When excised embryos of Agrostemma githago were incubated with nitrate, the activities of both nitrate reductase and nitrite reductase were enhanced. By contrast, benzyladenine induced nitrate reductase only. Our data suggest that nitrate affected nitrite reductase activity directly, without first being reduced to nitrite. When the endogenous nitrite production was increased by raising the level of nitrate reductase through simultaneous treatment with nitrate and benzyladenine, the activity of nitrite reductase was not higher than in embryos treated with nitrate alone. On the other hand, tungstate given together with nitrate drastically inhibited the development of nitrate reductase activity without reducing the enhancement of nitrite reductase activity. Nitrite enhanced nitrite reductase activity, though less efficiently than nitrate.
Tungstate
Cite
Citations (13)
Although the effects of environmental changes on extractable nitrate reductase activity are well documented, little attention has been paid to the response of nitrite reductase to similar treatments. We have followed changes in the level of extractable nitrate and nitrite reductase in the leaves of pea seedlings subjected to different light, shade, drought, and nitrate treatments. In similarity to nitrate reductase, extractable nitrite reductase increases with availability of nitrate. However, it appears that the two enzyme activities show differential responses in plants exposed to drought conditions and in plants transferred to darkness. Nitrate reductase activity declines much more rapidly than nitrite reductase. These observations and the varying influence of the other environmental treatments are discussed in relation to the different cellular locations of nitrate and nitrite reductase.
Cite
Citations (25)