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Lu J, Tan Y, Tian S, Qin Y, Zhou M, Hu H, Zhao X, Wang Z, Hu B. Effect of carbon source on carbon and nitrogen metabolism of common heterotrophic nitrification-aerobic denitrification pathway. CHEMOSPHERE 2024; 361:142525. [PMID: 38838867 DOI: 10.1016/j.chemosphere.2024.142525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 05/10/2024] [Accepted: 06/02/2024] [Indexed: 06/07/2024]
Abstract
Pseudomonas sp. ZHL02, removing nitrogen via ammonia nitrogen (NH4+) → hydroxylamine (HN2OH) → nitrite (NO2-) → nitrate (NO3-) → NO2- → nitric oxide (NO) → nitrous oxide (N2O) pathway was employed for getting in-depth information on the heterotrophic nitrification-aerobic denitrification (HNAD) pathway from carbon oxidation, nitrogen conversion, electron transport process, enzyme activity, as well as gene expression while sodium succinate, sodium citrate, and sodium acetate were utilized as the carbon sources. The nitrogen balance analysis results demonstrated that ZHL02 mainly removed NH4+-N through assimilation. The carbon source metabolism resulted in the discrepancies in electron transport chain and nitrogen removal between different HNAD bacteria. Moreover, the prokaryotic strand-specific transcriptome method showed that, amo and hao were absent in ZHL02, and unknown genes may be involved in ZHL02 during the HNAD process. As a fascinating process for removing nitrogen, the HNAD process is still puzzling, and the relationship between carbon metabolism and nitrogen metabolism among different HNAD pathways should be studied further.
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Affiliation(s)
- Jiyan Lu
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Yue Tan
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Shanghong Tian
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Yuxiao Qin
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Meng Zhou
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Hao Hu
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Xiaohong Zhao
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Zhoufeng Wang
- School of Water and Environment, Changan University, Xian, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China.
| | - Bo Hu
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China.
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Nie L, Xiao Y, Zhou T, Feng H, He M, Liang Q, Mu K, Nie H, Huang Q, Chen W. Cyclic di-GMP inhibits nitrate assimilation by impairing the antitermination function of NasT in Pseudomonas putida. Nucleic Acids Res 2024; 52:186-203. [PMID: 38000372 PMCID: PMC10783516 DOI: 10.1093/nar/gkad1117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 11/02/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
The ubiquitous bacterial second messenger cyclic diguanylate (c-di-GMP) coordinates diverse cellular processes through its downstream receptors. However, whether c-di-GMP participates in regulating nitrate assimilation is unclear. Here, we found that NasT, an antiterminator involved in nitrate assimilation in Pseudomonas putida, specifically bound c-di-GMP. NasT was essential for expressing the nirBD operon encoding nitrite reductase during nitrate assimilation. High-level c-di-GMP inhibited the binding of NasT to the leading RNA of nirBD operon (NalA), thus attenuating the antitermination function of NasT, resulting in decreased nirBD expression and nitrite reductase activity, which in turn led to increased nitrite accumulation in cells and its export. Molecular docking and point mutation assays revealed five residues in NasT (R70, Q72, D123, K127 and R140) involved in c-di-GMP-binding, of which R140 was essential for both c-di-GMP-binding and NalA-binding. Three diguanylate cyclases (c-di-GMP synthetases) were found to interact with NasT and inhibited nirBD expression, including WspR, PP_2557, and PP_4405. Besides, the c-di-GMP-binding ability of NasT was conserved in the other three representative Pseudomonas species, including P. aeruginosa, P. fluorescens and P. syringae. Our findings provide new insights into nitrate assimilation regulation by revealing the mechanism by which c-di-GMP inhibits nitrate assimilation via NasT.
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Affiliation(s)
- Liang Nie
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yujie Xiao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Tiantian Zhou
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Haoqi Feng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Meina He
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qingyuan Liang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Kexin Mu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hailing Nie
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiaoyun Huang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenli Chen
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
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3
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Arya CK, Maurya S, Ramanathan G. Insight into the metabolic pathways of Paracoccus sp. strain DMF: a non-marine halotolerant methylotroph capable of degrading aliphatic amines/amides. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:125947-125964. [PMID: 38010547 DOI: 10.1007/s11356-023-30858-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 10/31/2023] [Indexed: 11/29/2023]
Abstract
Paracoccus sp. strain DMF (P. DMF from henceforth) is a gram-negative heterotroph known to tolerate and utilize high concentrations of N,N-dimethylformamide (DMF). The work presented here elaborates on the metabolic pathways involved in the degradation of C1 compounds, many of which are well-known pollutants and toxic to the environment. Investigations on microbial growth and detection of metabolic intermediates corroborate the outcome of the functional genome analysis. Several classes of C1 compounds, such as methanol, methylated amines, aliphatic amides, and naturally occurring quaternary amines like glycine betaine, were tested as growth substrates. The detailed growth and kinetic parameter analyses reveal that P. DMF can efficiently aerobically degrade trimethylamine (TMA) and grow on quaternary amines such as glycine betaine. The results show that the mechanism for halotolerant adaptation in the presence of glycine betaine is dissimilar from those observed for conventional trehalose-mediated halotolerance in heterotrophic bacteria. In addition, a close genomic survey revealed the presence of a Co(I)-based substrate-specific corrinoid methyltransferase operon, referred to as mtgBC. This demethylation system has been associated with glycine betaine catabolism in anaerobic methanogens and is unknown in denitrifying aerobic heterotrophs. This report on an anoxic-specific demethylation system in an aerobic heterotroph is unique. Our finding exposes the metabolic potential for the degradation of a variety of C1 compounds by P. DMF, making it a novel organism of choice for remediating a wide range of possible environmental contaminants.
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Affiliation(s)
- Chetan Kumar Arya
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Shiwangi Maurya
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Gurunath Ramanathan
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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Maurya S, Arya CK, Parmar N, Sathyanarayanan N, Joshi CG, Ramanathan G. Genomic profiling and characteristics of a C1 degrading heterotrophic fresh-water bacterium Paracoccus sp. strain DMF. Arch Microbiol 2023; 206:6. [PMID: 38015256 DOI: 10.1007/s00203-023-03729-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/29/2023]
Abstract
Paracoccus species are metabolically versatile gram-negative, aerobic facultative methylotrophic bacteria showing enormous promise for environmental and bioremediation studies. Here we report, the complete genome analysis of Paracoccus sp. strain DMF (P. DMF) that was isolated from a domestic wastewater treatment plant in Kanpur, India (26.4287 °N, 80.3891 °E) based on its ability to degrade a recalcitrant organic solvent N, N-dimethylformamide (DMF). The results reveal a genome size of 4,202,269 base pairs (bp) with a G + C content of 67.9%. The assembled genome comprises 4141 coding sequences (CDS), 46 RNA sequences, and 2 CRISPRs. Interestingly, catabolic operons related to the conventional marine-based methylated amines (MAs) degradation pathway were functionally annotated within the genome of an obligated aerobic heterotroph that is P. DMF. The genomic data-based characterization presented here for the novel heterotroph P. DMF aims to improve the understanding of the phenotypic gene products, enzymes, and pathways involved with greater emphasis on facultative methylotrophic motility-based latent pathogenicity.
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Affiliation(s)
- Shiwangi Maurya
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Chetan Kumar Arya
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Nidhi Parmar
- Gujarat Biotechnology Research Centre (GBRC), Gandhinagar, Gujarat, 382 011, India
| | - Nitish Sathyanarayanan
- Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, 560065, India
| | - Chaitanya G Joshi
- Gujarat Biotechnology Research Centre (GBRC), Gandhinagar, Gujarat, 382 011, India
| | - Gurunath Ramanathan
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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Zhou X, Wang Y, Tan X, Sheng Y, Li Y, Zhang Q, Xu J, Shi Z. Genomics and nitrogen metabolic characteristics of a novel heterotrophic nitrifying-aerobic denitrifying bacterium Acinetobacter oleivorans AHP123. BIORESOURCE TECHNOLOGY 2023; 375:128822. [PMID: 36871698 DOI: 10.1016/j.biortech.2023.128822] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/21/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
A novel aerobic strain of Acinetobacter oleivorans AHP123 was isolated from activated sludge, which could conduct heterotrophic nitrification and denitrification simultaneously. This strain has excellent NH4+-N removal ability, with 97.93% removal rate at 24-hour. To identify the metabolic pathways of this novel strain, genes of gam, glnA, gdhA, gltB, nirB, nasA, nar, nor, glnK and amt were detected by genome analysis. Through RT-qPCR, it was found that the expression of key genes confirmed two possible ways of nitrogen removal in strain AHP123: nitrogen assimilation and heterotrophic nitrification aerobic denitrification (HNAD). However, the absence of some common HNAD genes (amo, nap and nos) suggested that strain AHP123 might have a different HNAD pathway from other HNAD bacteria. Nitrogen balance analysis revealed that strain AHP123 assimilated most of the external nitrogen sources into intracellular nitrogen.
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Affiliation(s)
- Xiangqun Zhou
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Yuanli Wang
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China; Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Xin Tan
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China; Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Yequan Sheng
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China; Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Yanbin Li
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China; Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Anhui Polytechnic University, Wuhu, Anhui 241000, China.
| | - Qin Zhang
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China; Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Jialu Xu
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Zhengsheng Shi
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China
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Qi Z, Gao A, Li L, Li Z, Zhang W, Dong S, Liu X. A novel strategy to improving Rhodobacter azotoformans denitrification efficiency: Insight into the role of a two-component system NtrX/Y in denitrification regulation. BIORESOURCE TECHNOLOGY 2023; 368:128349. [PMID: 36400277 DOI: 10.1016/j.biortech.2022.128349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 06/16/2023]
Abstract
Transcription factors (TFs) can manage the coordinated expression of genes clusters or multiple genes. TF was used to improve bacterial denitrification ability in this study. During denitrification, the ntrY of R. azotoformans, which encodes the sensor of NtrX/Y system, was significantly upregulated in transcription. Denitrification of the mutant △ntrY was significantly inhibited, and it was recovered after replenishing this gene to the mutant, which indicates the NtrX/Y system plays an important role in regulating bacterial denitrification. According to additional research, the NtrX/Y system regulates bacterial denitrification by directly promoting the expression of the nitrite reductase. ntrY overexpression appears to accelerate bacterial denitrification, and the introduction of a strong promoter tac in conjunction with iron supply optimization increases the rate by 72% further. This study realizes bacterial denitrification enhancement from the perspective of global transcription regulation, which provides a novel strategy for improving microbial ability to degrade pollutants.
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Affiliation(s)
- Zhengliang Qi
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China.
| | - Anxin Gao
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Lu Li
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Zhen Li
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Wenyue Zhang
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Shuhan Dong
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Xinli Liu
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
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The NtrYX Two-Component System of Paracoccus denitrificans Is Required for the Maintenance of Cellular Iron Homeostasis and for a Complete Denitrification under Iron-Limited Conditions. Int J Mol Sci 2022; 23:ijms23169172. [PMID: 36012437 PMCID: PMC9409073 DOI: 10.3390/ijms23169172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 02/08/2023] Open
Abstract
Denitrification consists of the sequential reduction of nitrate to nitrite, nitric oxide, nitrous oxide, and dinitrogen. Nitrous oxide escapes to the atmosphere, depending on copper availability and other environmental factors. Iron is also a key element because many proteins involved in denitrification contain iron-sulfur or heme centers. The NtrYX two-component regulatory system mediates the responses in a variety of metabolic processes, including denitrification. A quantitative proteomic analysis of a Paracoccus denitrificans NtrY mutant grown under denitrifying conditions revealed the induction of different TonB-dependent siderophore transporters and proteins related to iron homeostasis. This mutant showed lower intracellular iron content than the wild-type strain, and a reduced growth under denitrifying conditions in iron-limited media. Under iron-rich conditions, it releases higher concentrations of siderophores and displayes lower nitrous oxide reductase (NosZ) activity than the wild-type, thus leading to nitrous oxide emission. Bioinformatic and qRT-PCR analyses revealed that NtrYX is a global transcriptional regulatory system that responds to iron starvation and, in turn, controls expression of the iron-responsive regulators fur, rirA, and iscR, the denitrification regulators fnrP and narR, the nitric oxide-responsive regulator nnrS, and a wide set of genes, including the cd1-nitrite reductase NirS, nitrate/nitrite transporters and energy electron transport proteins.
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Li Z, Li L, Sun H, Wang W, Yang Y, Qi Z, Liu X. Ammonia assimilation: A double-edged sword influencing denitrification of Rhodobacter azotoformans and for nitrogen removal of aquaculture wastewater. BIORESOURCE TECHNOLOGY 2022; 345:126495. [PMID: 34883195 DOI: 10.1016/j.biortech.2021.126495] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 06/13/2023]
Abstract
NO3--N and NH4+-N are two prevalent nitrogenous pollutants in aquaculture wastewater posing a significant health risk to aquatic animals. R. azotoformans ATCC17025 can rapidly denitrify to remove NO3--N, assimilating NH4+-N. The study investigated the influence of ammonia assimilation on bacterial denitrification. Results revealed that low concentration of NH4+-N (≤0.3 mM) accelerated denitrification, whereas high concentration inhibited it. RT-qPCR indicated that the inhibition of NO reduction under high concentration of NH4+-N was the primary cause of denitrification depression, whereas low concentration of NH4+-N enhanced the synthesis of practically all enzymes involved in denitrification. Finally, nitrogen-rich aquaculture effluent was effectively treated in lab-scale using a semi-continuous operation that provided an appropriate NH4+-N concentration for denitrification. This semi-continuous operation treated wastewater 2 times faster than the batch operation and the content of nitrogen decreased to effluent standard. The study can provide guidance for nitrogen removal of aquaculture wastewater with bioaugmentation.
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Affiliation(s)
- Zhen Li
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Lu Li
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Haoyu Sun
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Wenjuan Wang
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Yuying Yang
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Zhengliang Qi
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China.
| | - Xinli Liu
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
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9
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RNA-Seq Provides New Insights into the Gene Expression Changes in Azoarcus olearius BH72 under Nitrogen-Deficient and Replete Conditions beyond the Nitrogen Fixation Process. Microorganisms 2021; 9:microorganisms9091888. [PMID: 34576783 PMCID: PMC8467165 DOI: 10.3390/microorganisms9091888] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 11/17/2022] Open
Abstract
Azoarcus olearius BH72 is an endophyte capable of biological nitrogen fixation (BNF) and of supplying nitrogen to its host plant. Our previous microarray approach provided insights into the transcriptome of strain BH72 under N2-fixation in comparison to ammonium-grown conditions, which already indicated the induction of genes not related to the BNF process. Due to the known limitations of the technique, we might have missed additional differentially expressed genes (DEGs). Thus, we used directional RNA-Seq to better comprehend the transcriptional landscape under these growth conditions. RNA-Seq detected almost 24% of the annotated genes to be regulated, twice the amount identified by microarray. In addition to confirming entire regulated operons containing known DEGs, the new approach detected the induction of genes involved in carbon metabolism and flagellar and twitching motility. This may support N2-fixation by increasing energy production and by finding suitable microaerobic niches. On the other hand, energy expenditures were reduced by suppressing translation and vitamin biosynthesis. Nonetheless, strain BH72 does not appear to be content with N2-fixation but is primed for alternative economic N-sources, such as nitrate, urea or amino acids; a strong gene induction of machineries for their uptake and assimilation was detected. RNA-Seq has thus provided a better understanding of a lifestyle under limiting nitrogen sources by elucidating hitherto unknown regulated processes.
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10
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Olaya-Abril A, Hidalgo-Carrillo J, Luque-Almagro VM, Fuentes-Almagro C, Urbano FJ, Moreno-Vivián C, Richardson DJ, Roldán MD. Effect of pH on the denitrification proteome of the soil bacterium Paracoccus denitrificans PD1222. Sci Rep 2021; 11:17276. [PMID: 34446760 PMCID: PMC8390676 DOI: 10.1038/s41598-021-96559-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 07/23/2021] [Indexed: 11/25/2022] Open
Abstract
Denitrification is a respiratory process by which nitrate is reduced to dinitrogen. Incomplete denitrification results in the emission of the greenhouse gas nitrous oxide and this is potentiated in acidic soils, which display reduced denitrification rates and high N2O/N2 ratios compared to alkaline soils. In this work, impact of pH on the proteome of the soil denitrifying bacterium Paracoccus denitrificans PD1222 was analysed with nitrate as sole energy and nitrogen source under anaerobic conditions at pH ranging from 6.5 to 7.5. Quantitative proteomic analysis revealed that the highest difference in protein representation was observed when the proteome at pH 6.5 was compared to the reference proteome at pH 7.2. However, this difference in the extracellular pH was not enough to produce modification of intracellular pH, which was maintained at 6.5 ± 0.1. The biosynthetic pathways of several cofactors relevant for denitrification and nitrogen assimilation like cobalamin, riboflavin, molybdopterin and nicotinamide were negatively affected at pH 6.5. In addition, peptide representation of reductases involved in nitrate assimilation and denitrification were reduced at pH 6.5. Data highlight the strong negative impact of pH on NosZ synthesis and intracellular copper content, thus impairing active NosZ assembly and, in turn, leading to elevated nitrous oxide emissions.
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Affiliation(s)
- Alfonso Olaya-Abril
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª planta, Campus de Rabanales, 14071, Córdoba, Spain
| | - Jesús Hidalgo-Carrillo
- Departamento de Química Orgánica, Universidad de Córdoba, Edificio Marie Curie, Campus de Rabanales, 14071, Córdoba, Spain
| | - Víctor M Luque-Almagro
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª planta, Campus de Rabanales, 14071, Córdoba, Spain
| | - Carlos Fuentes-Almagro
- Servicio Central de Apoyo a la Investigación (SCAI), Unidad de Proteómica, Universidad de Córdoba, Campus de Rabanales, 14071, Córdoba, Spain
| | - Francisco J Urbano
- Departamento de Química Orgánica, Universidad de Córdoba, Edificio Marie Curie, Campus de Rabanales, 14071, Córdoba, Spain
| | - Conrado Moreno-Vivián
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª planta, Campus de Rabanales, 14071, Córdoba, Spain
| | - David J Richardson
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - María Dolores Roldán
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª planta, Campus de Rabanales, 14071, Córdoba, Spain.
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11
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Wang L, Shao Z. Aerobic Denitrification and Heterotrophic Sulfur Oxidation in the Genus Halomonas Revealed by Six Novel Species Characterizations and Genome-Based Analysis. Front Microbiol 2021; 12:652766. [PMID: 33815342 PMCID: PMC8014003 DOI: 10.3389/fmicb.2021.652766] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/09/2021] [Indexed: 11/16/2022] Open
Abstract
Bacteria of Halomonas are widely distributed in various environments and play a substantial role in the nutrient cycle. In this report, 14 strains capable of aerobic denitrification and heterotrophic sulfur oxidation were isolated from different habitats. Based on the phenotypic, genotypic, and chemotaxonomic analyses, these strains were considered to represent six novel species of the genus Halomonas, for which the names Halomonas zhangzhouensis sp. nov. type strain CXT3-11T ( = MCCC 1A11036T = KCTC 72087T), Halomonas aerodenitrificans sp. nov. CYD-9T ( = MCCC 1A11058T = KCTC 72088T), Halomonas sulfidoxydans sp. nov. CYN-1-2T ( = MCCC 1A11059T = KCTC 72089T), Halomonas ethanolica sp. nov. CYT3-1-1T ( = MCCC 1A11081T = KCTC 72090T), Halomonas sulfidivorans sp. nov. NLG_F1ET ( = MCCC 1A13718T = KCTC 72091T), and Halomonas tianxiuensis sp. nov. BC-M4-5T ( = MCCC 1A14433T = KCTC 72092T) are proposed. Intriguingly, they formed a unique group with 11 other species designated as the "H. desiderata group." To better understand their featured metabolisms, genes involved in denitrification and sulfur oxidation were analyzed, along with 193 other available genomes of the whole genus. Consistently, complete denitrification pathways were confirmed in the "H. desiderata group," in which napA, narG, nirS, norB, and nosZ genes coexist. Their nitrite reductase NirS formed a unique evolutionary lineage, distinguished from other denitrifiers in Halomonas. In addition, diverse occurrence patterns of denitrification genes were also observed in different phylogenetic clades of Halomonas. With respect to sulfur oxidation, fccAB genes involved in sulfide oxidation commonly exist in the "H. desiderata group," while sqr genes are diverse and can be found in more species; sqr genes co-occurred with fccAB in eight strains of this study, contributing to more active sulfide oxidation. Besides, the tsdA gene, which encodes an enzyme that oxidizes thiosulfate to tetrathionate, is ubiquitous in the genus Halomonas. The widespread presence of sqr/fccAB, pdo, and tsdA in Halomonas suggests that many Halomonas spp. can act as heterotrophic sulfur oxidizers. These results provide comprehensive insights into the potential of denitrification and sulfur oxidation in the whole genus of Halomonas. With regard to the global distribution of Halomonas, this report implies their unneglectable role in the biogeochemical cycle.
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Affiliation(s)
- Liping Wang
- School of Environment, Harbin Institute of Technology, Harbin, China
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, State Key Laboratory Breeding Base of Marine Genetic Resources, Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China
| | - Zongze Shao
- School of Environment, Harbin Institute of Technology, Harbin, China
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, State Key Laboratory Breeding Base of Marine Genetic Resources, Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
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12
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Sánchez C, Siqueira AF, Mitsui H, Minamisawa K. Identification of Genes Regulated by the Antitermination Factor NasT during Denitrification in Bradyrhizobium diazoefficiens. Microbes Environ 2019; 34:260-267. [PMID: 31257307 PMCID: PMC6759348 DOI: 10.1264/jsme2.me19033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The soybean symbiont Bradyrhizobium diazoefficiens grows anaerobically in the presence of nitrate using the denitrification pathway, which involves the nap, nir, nor, and nos genes. We previously showed that NasT acts as a transcription antitermination regulator for nap and nos gene expression. In the present study, we investigated the targets of NasT in B. diazoefficiens during denitrifying growth by performing transcription profiling with RNA-seq and quantitative reverse-transcription PCR. Most of the genes with altered expression in the absence of NasT were related to nitrogen metabolism, specifically several systems for branched-chain amino acid transport. The present results suggest that the reduced expression of genes involved in nitrogen acquisition leads to the induction of alternative sets of genes with similar functions. The ΔnasT mutant of B. diazoefficiens grew better than the wild type under denitrifying conditions. However, this enhanced growth was completely abolished by an additional loss of the narK or bjgb genes, which encode cytoplasmic systems for nitrite and nitric oxide detoxification, respectively. Since the expression of narK and bjgb was increased in the ΔnasT mutant, the growth of the ΔnasT mutant may be promoted by increased detoxification activity.
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13
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Saranathan N, Vivekanandan P. G-Quadruplexes: More Than Just a Kink in Microbial Genomes. Trends Microbiol 2019; 27:148-163. [PMID: 30224157 PMCID: PMC7127049 DOI: 10.1016/j.tim.2018.08.011] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/17/2018] [Accepted: 08/24/2018] [Indexed: 02/06/2023]
Abstract
G-quadruplexes (G4s) are noncanonical nucleic acid secondary structures formed by guanine-rich DNA and RNA sequences. In this review we aim to provide an overview of the biological roles of G4s in microbial genomes with emphasis on recent discoveries. G4s are enriched and conserved in the regulatory regions of microbes, including bacteria, fungi, and viruses. Importantly, G4s in hepatitis B virus (HBV) and hepatitis C virus (HCV) genomes modulate genes crucial for virus replication. Recent studies on Epstein-Barr virus (EBV) shed light on the role of G4s within the microbial transcripts as cis-acting regulatory signals that modulate translation and facilitate immune evasion. Furthermore, G4s in microbial genomes have been linked to radioresistance, antigenic variation, recombination, and latency. G4s in microbial genomes represent novel therapeutic targets for antimicrobial therapy.
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Affiliation(s)
- Nandhini Saranathan
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Perumal Vivekanandan
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India.
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14
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Olaya-Abril A, Hidalgo-Carrillo J, Luque-Almagro VM, Fuentes-Almagro C, Urbano FJ, Moreno-Vivián C, Richardson DJ, Roldán MD. Exploring the Denitrification Proteome of Paracoccus denitrificans PD1222. Front Microbiol 2018; 9:1137. [PMID: 29896187 PMCID: PMC5987163 DOI: 10.3389/fmicb.2018.01137] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 05/14/2018] [Indexed: 11/24/2022] Open
Abstract
Denitrification is a respiratory process that produces nitrous oxide as an intermediate, which may escape to the atmosphere before its reduction to dinitrogen through the nitrous oxide reductase NosZ. In this work, the denitrification process carried out by Paracoccus denitrificans PD1222 has been explored through a quantitative proteomic analysis. Under anaerobic conditions, with nitrate as sole nitrogen source, the synthesis of all the enzymes involved in denitrification, the respiratory nitrate, nitrite, nitric oxide, and nitrous oxide reductases, was increased. However, the periplasmic and assimilatory nitrate reductases decreased. Synthesis of transporters for alcohols, D-methionine, sulfate and copper, most of the enzymes involved in the tricarboxylic acid cycle, and proteins involved in other metabolic processes like lysine catabolism, fatty acids degradation and acetyl-CoA synthesis, was increased during denitrification in P. denitrificans PD1222. As consequence, an enhanced production of the central metabolite acetyl-CoA was observed. After establishing the key features of the denitrification proteome, its changes by the influence of a competitive electron acceptor, oxygen, or competitive nitrogen source, ammonium, were evaluated.
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Affiliation(s)
- Alfonso Olaya-Abril
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Córdoba, Spain
| | | | | | | | | | - Conrado Moreno-Vivián
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Córdoba, Spain
| | - David J. Richardson
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - María D. Roldán
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Córdoba, Spain
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15
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Olaya-Abril A, Luque-Almagro VM, Manso I, Gates AJ, Moreno-Vivián C, Richardson DJ, Roldán MD. Poly(3-hydroxybutyrate) hyperproduction by a global nitrogen regulator NtrB mutant strain of Paracoccus denitrificans PD1222. FEMS Microbiol Lett 2018; 365:4705890. [PMID: 29228177 PMCID: PMC5812496 DOI: 10.1093/femsle/fnx251] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 11/29/2017] [Indexed: 12/27/2022] Open
Abstract
Paracoccus denitrificans PD1222 accumulates short-length polyhydroxyalkanoates, poly(3-hydroxybutyrate), under nitrogen-deficient conditions. Polyhydroxybutyrate metabolism requires the 3-ketoacyl-CoA thiolase PhaA, the acetoacetyl-CoA dehydrogenase/reductase PhaB and the synthase PhaC for polymerization. Additionally, P. denitrificans PD1222 grows aerobically with nitrate as sole nitrogen source. Nitrate assimilation is controlled negatively by ammonium through the two-component NtrBC system. NtrB is a sensor kinase that autophosphorylates a histidine residue under low-nitrogen concentrations and, in turn, transfers a phosphoryl group to an aspartate residue of the response regulator NtrC protein, which acts as a transcriptional activator of the P. denitrificans PD1222 nasABGHC genes. The P. denitrificans PD1222 NtrB mutant was unable to use nitrate efficiently as nitrogen source when compared to the wild-type strain, and it also overproduced poly(3-hydroxybutyrate). Acetyl-CoA concentration in the P. denitrificans PD1222 NtrB mutant strain was higher than in the wild-type strain. The expression of the phaC gene was also increased in the NtrB mutant when compared to the wild-type strain. These results suggest that accumulation of poly(3-hydroxybutyrate) in the NtrB mutant strain of PD1222 responds to the high levels of acetyl-CoA that accumulate in the cytoplasm as consequence of its inability to efficiently use nitrate as nitrogen source.
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Affiliation(s)
- Alfonso Olaya-Abril
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1a planta, Campus de Rabanales, Córdoba, 14071, Spain
| | - Víctor M Luque-Almagro
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1a planta, Campus de Rabanales, Córdoba, 14071, Spain
| | - Isabel Manso
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1a planta, Campus de Rabanales, Córdoba, 14071, Spain
| | - Andrew J Gates
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Conrado Moreno-Vivián
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1a planta, Campus de Rabanales, Córdoba, 14071, Spain
| | - David J Richardson
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - María Dolores Roldán
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1a planta, Campus de Rabanales, Córdoba, 14071, Spain
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