scholarly journals Enrichment and physiological characterization of a novel comammox Nitrospira indicates ammonium inhibition of complete nitrification

2020 ◽  
Author(s):  
Dimitra Sakoula ◽  
Hanna Koch ◽  
Jeroen Frank ◽  
Mike SM Jetten ◽  
Maartje AHJ van Kessel ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Enrichment Culture ◽  
Substrate Inhibition ◽  
Wide Distribution ◽  
Metagenomic Sequencing ◽  
Physiological Characterization ◽  
Physiological Properties ◽  
Ammonium Tolerance ◽  
Determining Factor

AbstractThe recent discovery of bacteria within the genus Nitrospira capable of complete ammonia oxidation (comammox) demonstrated that the sequential oxidation of ammonia to nitrate via nitrite can also be performed within a single bacterial cell. Although comammox Nitrospira exhibit a wide distribution in natural and engineered ecosystems, information on their physiological properties is scarce due to the limited number of cultured representatives. Furthermore, most available genomic information is derived from metagenomic sequencing and high-quality genomes of Nitrospira in general are limited. In this study, we obtained a high (90%) enrichment of a novel comammox species, tentatively named “Candidatus Nitrospira kreftii”, and performed a detailed genomic and physiological characterization. The complete genome of “Ca. N. kreftii” allowed reconstruction of its basic metabolic traits. Similar to Nitrospira inopinata, the enrichment culture exhibited a very high ammonia affinity (Km(app)_NH3 ≈ 0.036 µM), but a higher nitrite affinity (Km(app)_NO2- ≈ 13.8 µM), indicating an adaptation to highly oligotrophic environments. Counterintuitively for a nitrifying microorganism, we also observed an inhibition of ammonia oxidation at ammonium concentrations as low as 25 µM. This substrate inhibition of “Ca. N. kreftii” indicate that differences in ammonium tolerance rather than affinity can be a niche determining factor for different comammox Nitrospira.

scholarly journals Enrichment and physiological characterization of a novel comammox Nitrospira indicates ammonium inhibition of complete nitrification

2020 ◽  
Author(s):  
Dimitra Sakoula ◽  
Hanna Koch ◽  
Jeroen Frank ◽  
Mike S. M. Jetten ◽  
Maartje A. H. J. van Kessel ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Enrichment Culture ◽  
Wide Distribution ◽  
Metagenomic Sequencing ◽  
Physiological Characterization ◽  
Physiological Properties ◽  
Ammonium Tolerance ◽  
Determining Factor ◽  
Very High

AbstractThe recent discovery of bacteria within the genus Nitrospira capable of complete ammonia oxidation (comammox) demonstrated that the sequential oxidation of ammonia to nitrate via nitrite can also be performed within a single bacterial cell. Although comammox Nitrospira exhibit a wide distribution in natural and engineered ecosystems, information on their physiological properties is scarce due to the limited number of cultured representatives. Additionally, most available genomic information is derived from metagenomic sequencing and high-quality genomes of Nitrospira in general are limited. In this study, we obtained a high (90%) enrichment of a novel comammox species, tentatively named “Candidatus Nitrospira kreftii”, and performed a detailed genomic and physiological characterization. The complete genome of “Ca. N. kreftii” allowed reconstruction of its basic metabolic traits. Similar to Nitrospira inopinata, the enrichment culture exhibited a very high ammonia affinity (Km(app)_NH3 ≈ 0.040 ± 0.01 µM), but a higher nitrite affinity (Km(app)_NO2- = 12.5 ± 4.0 µM), indicating an adaptation to highly oligotrophic environments. Furthermore, we observed partial inhibition of ammonia oxidation at ammonium concentrations as low as 25 µM. This inhibition of “Ca. N. kreftii” indicates that differences in ammonium tolerance rather than affinity could potentially be a niche determining factor for different comammox Nitrospira.

scholarly journals Ecophysiological Characterization of Ammonia-Oxidizing Archaea and Bacteria from Freshwater

2012 ◽  
Vol 78 (16) ◽  
pp. 5773-5780 ◽  
Author(s):  
Elizabeth French ◽  
Jessica A. Kozlowski ◽  
Maitreyee Mukherjee ◽  
George Bullerjahn ◽  
Annette Bollmann
Keyword(s):  
Growth Rates ◽  
Ammonia Oxidation ◽  
Light Exposure ◽  
Enrichment Culture ◽  
Ammonia Oxidizing Bacteria ◽  
Content Type ◽  
Ammonia Oxidizing Archaea ◽  
Group I ◽  
Nitrosomonas Oligotropha

ABSTRACTAerobic biological ammonia oxidation is carried out by two groups of microorganisms, ammonia-oxidizing bacteria (AOB) and the recently discovered ammonia-oxidizing archaea (AOA). Here we present a study using cultivation-based methods to investigate the differences in growth of three AOA cultures and one AOB culture enriched from freshwater environments. The strain in the enriched AOA culture belong to thaumarchaeal group I.1a, with the strain in one enrichment culture having the highest identity with “CandidatusNitrosoarchaeum koreensis” and the strains in the other two representing a new genus of AOA. The AOB strain in the enrichment culture was also obtained from freshwater and had the highest identity to AOB from theNitrosomonas oligotrophagroup (Nitrosomonascluster 6a). We investigated the influence of ammonium, oxygen, pH, and light on the growth of AOA and AOB. The growth rates of the AOB increased with increasing ammonium concentrations, while the growth rates of the AOA decreased slightly. Increasing oxygen concentrations led to an increase in the growth rate of the AOB, while the growth rates of AOA were almost oxygen insensitive. Light exposure (white and blue wavelengths) inhibited the growth of AOA completely, and the AOA did not recover when transferred to the dark. AOB were also inhibited by blue light; however, growth recovered immediately after transfer to the dark. Our results show that the tested AOB have a competitive advantage over the tested AOA under most conditions investigated. Further experiments will elucidate the niches of AOA and AOB in more detail.

Multidimensional Reveal of Nitrogen Regulation on Comammox

2020 ◽  
Author(s):  
Yuxiang Zhao ◽  
Jiajie Hu ◽  
Weiling Yang ◽  
Jiaqi Wang ◽  
Zhongjun Jia ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Nitrate Reduction ◽  
Ammonia Oxidation ◽  
Enrichment Culture ◽  
Ammonia Oxidizer ◽  
Nitrification Rate ◽  
Ammonia Oxidizing Bacteria ◽  
Metagenomic Sequencing ◽  
Sole Nitrogen Source ◽  
Total Bacteria

Abstract Background The discovery of complete ammonia oxidizer (comammox) was groundbreaking. Comammox can use ammonia as the sole nitrogen source and turn it to nitrate. Moreover, genomic data indicated that comammox contained genes which can metabolize urea and nitrite. However, the feasibility of enriching comammox with urea and nitrite in long term has not been proved. This study enriched comammox’s culture by using nitrite in reactor SA and urea in reactor SB. Results The nitrification rate of reactor SB (1.29 mg N·g -1 biofilm · d -1 ) was higher than that in reactor SA (0.6 mg N · g -1 biofilm · d -1 ) at the 390 th day. Comammox outnumbered ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in both reactor SA (9.04 × 10 9 copies / g biofilm) and reactor SB (5.34×10 10 copies/ g biofilm). In reactor SA, comammox’s amoA accounted for 92% of the total amoA, which was higher than that in reactor SB (85%). However, the percentage of comammox (4%) in total bacteria was much lower than reactor SB (14%). The results of metagenomic sequencing showed that all the pathways of nitrogen cycle including nitrification, nitrogen fixation, denitrification, assimilation nitrate reduction, and dissimilation nitrate reduction can be detected in both reactor SA and reactor SB except the anammox pathway. The genes related to nitrite oxidation and nitrate reduction in reactor SA (TPM = 5099; TPM = 3329) was higher than that of in reactor SB (TPM = 4071; TPM = 2984), presumably due to the demand of turning nitrite to nitrate and turning nitrate to ammonia. While genes related to ammonia oxidation and urea metabolism in reactor SB (TPM = 3915; TPM = 3638) was higher than that in reactor SA (TPM = 2708; TPM = 3002). Conclusion Nitrite and urea can regulate the enrichment culture of comammox by converting its metabolic pathway. Using nitrite as sole nitrogen source can improve the proportion comammox’s amoA in total amoA while using urea as the sole nitrogen source may increase comammox’s proportion in total bacteria. These results can accelerate the enrichment of comammox and facilitate the promotion of comammox’s engineering operation.

Characterization of the Serum a1-Antitripsine Level in Primary Spontaneous Pneumotorax Patients

2018 ◽  
Vol 69 (9) ◽  
pp. 2591-2593
Author(s):  
Cristina Grigorescu ◽  
Liviu Ciprian Gavril ◽  
Laura Gavril ◽  
Tiberiu Lunguleac ◽  
Bogdan Mihnea Ciuntu ◽  
...  
Keyword(s):  
Serum Level ◽  
Pulmonary Emphysema ◽  
Spontaneous Pneumothorax ◽  
Antitrypsin Deficiency ◽  
Alpha 1 Antitrypsin Deficiency ◽  
Alpha 1 Antitrypsin ◽  
Determining Factor

Diagnosis of primary or idiopathic spontaneous pneumothorax is one of exclusion, and in fact defines an entity that may have a difficult or impossible cause to be highlighted by current means, we consider it appropriate to study these etiopathogenic aspects. There is a definite association between alpha-1 antitrypsin deficiency and pulmonary emphysema and indirect spontaneous pneumothorax secondary to an emphysematous pulmonary lesion. Dose of alpha-1 antitrypsin is an immunoturbinimetric method for in vitro determination of alpha-1 antitrypsin in human serum and plasma. This product is calibrated to be used for the Daytona RX analyzer. The serum level of alpha-1-antitrypsin is not a determining factor in the postoperative evolution characterized by the interval until air loss disappears, but certainly exerts some influence, the exact level of which remains to be determined.

Enrichment and characterization of an anaerobic methyl ethyl ketoxime degrading culture from an anoxic/anaerobic/aerobic activated sludge sequencing batch reactor

1998 ◽  
Vol 37 (4-5) ◽  
pp. 95-98 ◽  
Author(s):  
Nancy G. Love ◽  
Mary E. Rust ◽  
Kathy C. Terlesky
Keyword(s):  
Energy Source ◽  
Activated Sludge ◽  
Electron Acceptor ◽  
Sequencing Batch Reactor ◽  
Enrichment Culture ◽  
Batch Reactor ◽  
Nitrification Inhibitor ◽  
Time Frame ◽  
Methyl Ethyl

An anaerobic enrichment culture was developed from an anoxic/anaerobic/aerobic activated sludge sequencing batch reactor using methyl ethyl ketoxime (MEKO), a potent nitrification inhibitor, as the sole carbon and energy source in the absence of molecular oxygen and nitrate. The enrichment culture was gradually fed decreasing amounts of biogenic organic compounds and increasing concentrations of MEKO over 23 days until the cultures metabolized the oxime as the sole carbon source; the cultures were maintained for an additional 41 days on MEKO alone. Turbidity stabilized at approximately 100 mg/l total suspended solids. Growth on selective media plates confirmed that the microorganisms were utilizing the MEKO as the sole carbon and energy source. The time frame required for growth indicated that the kinetics for MEKO degradation are slow. A batch test indicated that dissolved organic carbon decreased at a rate comparable to MEKO consumption, while sulfate was not consumed. The nature of the electron acceptor in anaerobic MEKO metabolism is unclear, but it is hypothesized that the MEKO is hydrolyzed intracellularly to form methyl ethyl ketone and hydroxylamine which serve as electron donor and electron acceptor, respectively.

Molecular and physiological characterization of Arabidopsis‐Colletotrichum gloeosporioides pathosystem

2021 ◽  
Author(s):  
Mengze Gao ◽  
Miting Wan ◽  
Liyun Yang ◽  
Meng Zhao ◽  
Xiaojin Liu ◽  
...  
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Physiological Characterization
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