scholarly journals Nitrate- and Nitrite-Sensing Histidine Kinases: Function, Structure, and Natural Diversity

2021 ◽  
Vol 22 (11) ◽  
pp. 5933
Author(s):  
Ivan Gushchin ◽  
Vladimir A. Aleksenko ◽  
Philipp Orekhov ◽  
Ivan M. Goncharov ◽  
Vera V. Nazarenko ◽  
...  

Under anaerobic conditions, bacteria may utilize nitrates and nitrites as electron acceptors. Sensitivity to nitrous compounds is achieved via several mechanisms, some of which rely on sensor histidine kinases (HKs). The best studied nitrate- and nitrite-sensing HKs (NSHKs) are NarQ and NarX from Escherichia coli. Here, we review the function of NSHKs, analyze their natural diversity, and describe the available structural information. In particular, we show that around 6000 different NSHK sequences forming several distinct clusters may now be found in genomic databases, comprising mostly the genes from Beta- and Gammaproteobacteria as well as from Bacteroidetes and Chloroflexi, including those from anaerobic ammonia oxidation (annamox) communities. We show that the architecture of NSHKs is mostly conserved, although proteins from Bacteroidetes lack the HAMP and GAF-like domains yet sometimes have PAS. We reconcile the variation of NSHK sequences with atomistic models and pinpoint the structural elements important for signal transduction from the sensor domain to the catalytic module over the transmembrane and cytoplasmic regions spanning more than 200 Å.

2009 ◽  
Vol 59 (12) ◽  
pp. 2405-2410 ◽  
Author(s):  
Ping Li ◽  
Lei Tong ◽  
Kun Liu ◽  
Yanhong Wang ◽  
Yanxin Wang

Three new strains named LPA11, LPB11 and LPC24 were isolated to investigate the patterns of indole degradation and ammonia oxidation in swine wastewater from different parts of a swine wastewater treatment system by the direct spreading plate method. These three isolates were all identified as Pseudomonas putida based on 16S-rDNA gene sequences, main physiological and biochemical analysis. They were capable of decomposing 1.0 mM indole completely in 10, 16 and 18 days respectively. According to the results of HPLC and GC/MS, the possible pathway for the degradation was via oxindole, isatin and anthranilic acid. The three bacteria were capable of oxidizing ammonia, and the strains LPA11 and LPC24 were capable of effectively reducing nitrate and nitrite.


1970 ◽  
Vol 8 (1-2) ◽  
pp. 119-125 ◽  
Author(s):  
Iswar Man Amatya ◽  
Bhagwan Ratna Kansakar ◽  
Vinod Tare ◽  
Liv Fiksdal

It is important to determine the effect of changing environmental conditions on the microbial kinetics for design and modeling of biological treatment processes. In this research, the kinetics of ammonia oxidation by nitrifying process bacteria under varying pH and temperature conditions are studied. Ammonia oxidation in groundwater was carried out by biological method of nitrification process. The nitrification was performed in one set of reactors. The reactor consists of two columns connected in series packed with over burnt bricks as media. The filtration rate varied from 10.5 to 210.4 m/day for nitrification process respectively. The ammonia, nitrate and nitrite nitrogen concentrations were measured at inlet, intermediate ports and outlet. The temperature varied from 10 to 30°C at 2°C intervals. The results demonstrated that high amounts of ammonia nitrogen nitrified in groundwater at nitrification process. The average ammonia nitrogen oxidation efficiency of 77.27% was achieved from pH 7.3 to 8.0 in the reactor packed with OBB media at 20°C, for the flow rate 500ml/min due to biological nitrification. The total amount of ammonia nitrogen removed by nitrification varied from 0.76 to 17.80 gm/m3/h at influent concentration from 2.84 to 149.28 gm/m3/h.Key words: Over burnt brick; Filtration rate; Temperature; Nitrification and Nitrifying bacteriaDOI: http://dx.doi.org/10.3126/jie.v8i1-2.5102Journal of the Institute of Engineering Vol. 8, No. 1&2, 2010/2011Page: 119-125Uploaded Date: 20 July, 2011


2017 ◽  
Vol 124 (3) ◽  
pp. 333-338 ◽  
Author(s):  
Tomotaka Nakamura ◽  
Yuhki Harigaya ◽  
Yuya Kimura ◽  
Megumi Kuroiwa ◽  
Yuhri Kurata ◽  
...  

2012 ◽  
Vol 32 (21) ◽  
pp. 6591-6598 ◽  
Author(s):  
王衫允 WANG Shanyun ◽  
祝贵兵 ZHU Guibing ◽  
曲冬梅 QU Dongmei ◽  
尹澄清 YIN Chengqing

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