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Li J, Zhao C, Li C, Xue B, Wang S, Zhang X, Yang X, Shen Z, Bo L, He X, Qiu Z, Wang J. Multidrug-resistant plasmid RP4 increases NO and N 2O yields via the electron transport system in Nitrosomonas europaea ammonia oxidation. WATER RESEARCH 2023; 242:120266. [PMID: 37421866 DOI: 10.1016/j.watres.2023.120266] [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: 01/03/2023] [Revised: 06/19/2023] [Accepted: 06/23/2023] [Indexed: 07/10/2023]
Abstract
Antibiotic resistance genes (ARGs) have recently become an important public health problem and therefore several studies have characterized ARG composition and distribution. However, few studies have assessed their impact on important functional microorganisms in the environment. Therefore, our study sought to investigate the mechanisms through which multidrug-resistant plasmid RP4 affected the ammonia oxidation capacity of ammonia-oxidizing bacteria, which play a key role in the nitrogen cycle. The ammonia oxidation capacity of N. europaea ATCC25978 (RP4) was significantly inhibited, and NO and N2O were produced instead of nitrite. Our findings demonstrated that the decrease in electrons from NH2OH decreased the ammonia monooxygenase (AMO) activity, leading to a decrease in ammonia consumption. In the ammonia oxidation process, N. europaea ATCC25978 (RP4) exhibited ATP and NADH accumulation. The corresponding mechanism was the overactivation of Complex Ⅰ, ATPase, and the TCA cycle by the RP4 plasmid. The genes encoding TCA cycle enzymes related to energy generation, including gltA, icd, sucD, and NE0773, were upregulated in N. europaea ATCC25978 (RP4). These results demonstrate the ecological risks of ARGs, including the inhibition of the ammonia oxidation process and an increased production of greenhouse gases such as NO and N2O.
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Affiliation(s)
- Jia Li
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Chen Zhao
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Chenyu Li
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Bin Xue
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Shang Wang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Xi Zhang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Xiaobo Yang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Zhiqiang Shen
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Lin Bo
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China; Tiangong University, Tianjin, China
| | - Xinxin He
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Zhigang Qiu
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China.
| | - Jingfeng Wang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China.
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Zhao B, Yang Y, Zhao C, Zhang C, Zhang Z, Wang L, Wang S, Wang J. Exploration of the metabolic flexibility of glycogen accumulating organisms through metatranscriptome analysis and metabolic characterization. J Environ Sci (China) 2023; 126:234-248. [PMID: 36503752 DOI: 10.1016/j.jes.2022.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/06/2022] [Accepted: 05/06/2022] [Indexed: 06/17/2023]
Abstract
Glycogen accumulating organisms (GAOs) are closely related to the deterioration of enhanced biological phosphorus removal systems. However, the metabolic mechanisms that drive GAOs remain unclear. Here, the two-thirds supernatant of a reactor were decanted following the anaerobic period to enrich GAOs. Long-term monitoring demonstrated that the system was stable and exhibited typical characteristics of GAOs metabolism. Acetate was completely consumed after 60 min of the anaerobic phase. The level of glycogen decreased from 0.20 to 0.14 g/gSS during the anaerobic phase, whereas the level of glycogen significantly increased to 0.21g/gSS at the end of the aerobic period. Moreover, there was almost no phosphate release and absorption in the complete periods, thus confirming the successful construction of a GAOs enrichment system. Microbial community analysis demonstrated that Ca. Contendobacter was among the core functional genera and showed the highest activity among all of the communities. Furthermore, our study is the first to identify the involvement of the ethyl-malonyl-CoA pathway in the synthesis of polyhydroxyvalerate via croR, ccr, ecm, mcd, mch and mcl genes. The Embden-Meyerhof-Parnas (EMP) pathway was preferentially used via glgP. Furthermore, the glyoxylate cycle was the main source of ATP under anaerobic conditions, whereas the tricarboxylic acid cycle provided ATP under aerobic conditions. aceA and mdh appeared to be major modulators of the glyoxylate pathway for controlling energy flow. Collectively, our findings not only revealed the crucial metabolic mechanisms in a GAOs enrichment system but also provided insights into the potential application of Ca. Contendobacter for wastewater treatment.
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Affiliation(s)
- Bin Zhao
- School of Environmental Science Engineering, Tiangong University, Tianjin 300387, China
| | - Yanping Yang
- School of Environmental Science Engineering, Tiangong University, Tianjin 300387, China; Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin 300201, China
| | - Chen Zhao
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin 300201, China
| | - Chunchun Zhang
- School of Environmental Science Engineering, Tiangong University, Tianjin 300387, China; Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin 300201, China
| | - Zhaohui Zhang
- School of Environmental Science Engineering, Tiangong University, Tianjin 300387, China
| | - Liang Wang
- School of Environmental Science Engineering, Tiangong University, Tianjin 300387, China
| | - Shang Wang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin 300201, China.
| | - Jingfeng Wang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin 300201, China.
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Chen X, Han W, Patel M, Wang Q, Li Q, Zhao S, Jia W. Inactivation of a pathogenic NDM-1-positive Escherichia coli strain and the resistance gene bla NDM-1 by TiO 2/UVA photocatalysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157369. [PMID: 35842147 DOI: 10.1016/j.scitotenv.2022.157369] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 06/06/2022] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
Proliferation of blaNDM-1 in water and wastewater is particularly concerning because of multidrug-resistance and horizontal transfer of the gene. In the present study, a pathogenic NDM-1-positive Escherichia coli strain (named E. coli NDM-1) and the blaNDM-1 gene were treated with titanium dioxide (TiO2)/ultraviolet A (UVA) photocatalysis. Effects of catalyst dose, UVA intensity, and phosphate on bacteria and intracellular and extracellular blaNDM-1 genes were determined. With increases in TiO2 dose and UVA intensity, the inactivation rate of E. coli NDM-1 increased greatly in saline solution. However, phosphate in water hindered adsorption of bacteria to TiO2 and partly changed the TiO2 photocatalytic pathway, resulting in low degradation efficiency. Although inactivation of E. coli NDM-1 was highly efficient, TiO2/UVA photocatalysis had little effect on removal of the blaNDM-1 gene. During the 2-h photocatalytic experiments, E. coli cells decreased by 4.7-log, while the blaNDM-1 gene decreased by 0.7- ~ 1.5-log. Moreover, the degradation rate of extracellular blaNDM-1 was ~2.7 times higher than that of intracellular genes. Abundance and transformation frequency of residual blaNDM-1 genes remained high, even when bacteria were completely inactivated, indicating potential health risks. Increases in treatment time and UVA irradiation intensity are needed to remove the blaNDM-1 gene to sufficiently low levels.
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Affiliation(s)
- Xi Chen
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou 221116, PR China
| | - Wenxuan Han
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou 221116, PR China
| | - Manisha Patel
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, United States
| | - Qian Wang
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou 221116, PR China
| | - Qilin Li
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, United States
| | - Shuang Zhao
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou 221116, PR China
| | - Wenlin Jia
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou 221116, PR China.
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Zhao C, Li J, Li C, Xue B, Wang S, Zhang X, Yang X, Shen Z, Bo L, Qiu Z, Wang J. Horizontal transfer of the multidrug resistance plasmid RP4 inhibits ammonia nitrogen removal dominated by ammonia-oxidizing bacteria. WATER RESEARCH 2022; 217:118434. [PMID: 35427829 DOI: 10.1016/j.watres.2022.118434] [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: 02/03/2022] [Revised: 04/02/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
Antibiotic resistance genes (ARGs) have become an important public health concern. Particularly, although several ARGs have been identified in wastewater treatment plants (WWTPs), very few studies have characterized their impacts on reactor performance. Therefore, our study sought to investigate the effect of a representative conjugative transfer plasmid (RP4) encoding multidrug resistance genes on ammonia oxidation. To achieve this, we established sequencing batch reactors (SBRs) and a conjugation model with E. coli donor strains carrying the RP4 plasmid and a typical ammonia-oxidating (AOB) bacterial strain (Nitrosomonas europaea ATCC 25978) as a recipient to investigate the effect of conjugative transfer of plasmid RP4 on AOB. Our findings demonstrated that the RP4 plasmid carried by the donor strains could be transferred to AOB in the SBR and to Nitrosomonas europaea ATCC 25978. In SBR treated with donor strains carrying the RP4 plasmid, ammonia removal efficiency continuously decreased to 71%. Once the RP4 plasmid entered N. europaea ATCC 25978 in the conjugation model, ammonia removal was significantly inhibited and nitrite generation was decreased. Furthermore, the expression of several functional genes related to ammonia oxidation in AOB was suppressed following the transfer of the RP4 plasmid, including amoA, amoC, hao, nirK, and norB. In contrast, the cytL gene encoding cytochrome P460 was upregulated. These results demonstrated the ecological risk of ARGs in WWTPs, and therefore measures must be taken to avoid their transfer.
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Affiliation(s)
- Chen Zhao
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China; Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin, China
| | - Jia Li
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Chenyu Li
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China; Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin, China
| | - Bin Xue
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China; Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin, China
| | - Shang Wang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Xi Zhang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Xiaobo Yang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Zhiqiang Shen
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Lin Bo
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China; Tiangong University, Tianjin, China
| | - Zhigang Qiu
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China; Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin, China.
| | - Jingfeng Wang
- Department of Hygienic Toxicology and Environmental Hygiene, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China; Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin, China.
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Shi YJ, Yang L, Liao SF, Zhang LG, Liao ZC, Lan MY, Sun F, Ying GG. Responses of aerobic granular sludge to fluoroquinolones: Microbial community variations, and antibiotic resistance genes. JOURNAL OF HAZARDOUS MATERIALS 2021; 414:125527. [PMID: 33676249 DOI: 10.1016/j.jhazmat.2021.125527] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/24/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
In this study, aerobic granular sludge (AGS) was operated under high levels of ammonium for removing three fluoroquinolones (FQs), i.e., ciprofloxacin (CFX), ofloxacin (OFX), and norfloxacin (NFX) at 3, 300, and 900 µg/L, respectively. Two key objectives were to investigate the differential distribution of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in sludge fractions and to evaluate correlations between ARGs and MGEs to nitrifying and denitrifying bacteria. AGS showed excellent stability under the exposure of FQs, with nitrite-oxidizing bacteria (NOB) more sensitive to FQs than ammonium-oxidizing bacteria (AOB). Specific oxygen utilization rates (SOUR) showed a reduction of 26.9% for NOB but only 4.0% of the reduced activity of AOB by 3 μg/L FQs. AGS performed better removal efficiencies for CFX and NFX than OFX, and the efficiencies increased with their elevated concentrations, except at 900 μg/L FQs. The elevated FQ concentrations led to a significant enrichment of intI1 and genus Thauera, while qnrD and qnrS showed no accumulation. Compared to nitrifiers, FQs relevant ARGs and the intI1 gene preferred to exist in denitrifiers, and the abundance of denitrifiers behaved a decreasing trend with the sludge size. Two quinoline-degrading bacteria were found in the AGS system, i.e., Alicycliphilus and Brevundimonas, possibly carrying qnrS and qnrD, respectively. Their relative abundance increased with the sludge size, which was 2.18% in sludge <0.5 mm and increased to 3.70% in sludge >2.0 mm, suggesting that the AGS may be a good choice in treating FQs-containing wastewater.
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Affiliation(s)
- Yi-Jing Shi
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Lei Yang
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
| | - Sheng-Fa Liao
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Li-Guo Zhang
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Zi-Cong Liao
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Min-Yi Lan
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Feng Sun
- School of Environmental Science and Engineering, Yangzhou University, 196 Huayang West Road, Yangzhou, Jiangsu 225127, China
| | - Guang-Guo Ying
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China.
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You F, Wei J, Cheng Y, Wen Z, Ding C, Guo Y, Wang K. A sensitive and stable visible-light-driven photoelectrochemical aptasensor for determination of oxytetracycline in tomato samples. JOURNAL OF HAZARDOUS MATERIALS 2020; 398:122944. [PMID: 32768827 DOI: 10.1016/j.jhazmat.2020.122944] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/22/2020] [Accepted: 05/10/2020] [Indexed: 05/12/2023]
Abstract
Sensitive detection of oxytetracycline (OTC) has attracted increasing attention worldwide due to the relationship between food safety and human health problems. In this work, a visible-light-driven photoelectrochemical (PEC) OTC aptasensor was constructed using Bi4VO8Cl/nitrogen-doped graphene quantum dots (Bi4VO8Cl/N-GQDs) nanohybrids as photoactive material and OTC aptamer as identification element. Owing to the well matched heterojunction of Bi4VO8Cl and nitrogen-doped graphene quantum dots (N-GQDs), the photogenerated electron-hole pairs could be separated effectively, so that the photocurrent intensity of as-prepared Bi4VO8Cl/N-GQDs nanohybrids was about 7 times higher than pure Bi4VO8Cl and had higher stability. The constructed "signal-off" PEC aptasensor realized OTC detection in tomato samples with excellent sensitivity, specificity and repeatability. The photocurrent decreased with the increase of OTC concentration in a range from 0.1 nM to 150 nM, and the detection limit was 0.03 nM (S/N = 3). The national standard method was used to compare with our method and the results were consistent.
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Affiliation(s)
- Fuheng You
- Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Jie Wei
- Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Yong Cheng
- Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Zuorui Wen
- Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Caifeng Ding
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, OE, School of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Yingshu Guo
- Collaborative Innovation Center of Tumor Marker Detection Technology, Equipment and Diagnosis-Therapy Integration in Universities of Shandong, Shandong Province Key Laboratory of Detection Technology for Tumor Makers, School of Chemistry and Chemical Engineering, Linyi University, Linyi 276005, PR China.
| | - Kun Wang
- Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China; Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, OE, School of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
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Wang Q, He J. Newly designed high-coverage degenerate primers for nitrogen removal mechanism analysis in a partial nitrification-anammox (PN/A) process. FEMS Microbiol Ecol 2020; 96:5679889. [PMID: 31845981 DOI: 10.1093/femsec/fiz202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/13/2019] [Indexed: 11/14/2022] Open
Abstract
Reliable tools for quantification of different functional populations are required to achieve stable, effective nutrients removal in partial nitrification and anammox (PN/A) processes. Here we report the design and validation of degenerate PCR primer pairs targeting anammox bacteria, aerobic ammonium-oxidizing bacteria (AeAOB) and nitrite-oxidizing bacteria (NOB) with high coverage but without sacrificing specificity. The new primer pairs are able to cover a broader range of the targeted populations (58.4 vs 21.7%, 49.5 vs 47.6%, 80.7 vs 57.2% and 70.5 vs 42.3% of anammox bacteria, AeAOB, Nitrobacter and Nitrospina, respectively) than previously published primers. Particularly, the Amx719F/875R primer can retrieve a larger number of 16S rRNA genes from different types of samples with amplicons covering all known anammox bacteria genera (100% coverage) including the recently found novel genus, Asahi BRW. These newly desinged primers will provide a more reliable molecular tool to investigate the mechanisms of nitrogen removal in PN/A processes, which can provide clearer links between reactor performance, the metabolic activities and abundances of functional populations, shedding light on conditions that are favorable to the establishment of stable PN/A.
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Affiliation(s)
- Qingkun Wang
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
| | - Jianzhong He
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
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Huang H, Liao J, Zheng X, Chen Y, Ren H. Low-level free nitrous acid efficiently inhibits the conjugative transfer of antibiotic resistance by altering intracellular ions and disabling transfer apparatus. WATER RESEARCH 2019; 158:383-391. [PMID: 31059932 DOI: 10.1016/j.watres.2019.04.046] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 06/09/2023]
Abstract
Recently, the dissemination of antibiotic resistance genes (ARGs) via plasmid-mediated conjugation has been reported to be facilitated by a series of contaminants. This has highlighted potential challenges to the effective control of this principal mode of horizontal transfer. In the present study, we found that low levels (<0.02 mgN/L) of free nitrous acid (FNA) remarkably inhibited (over 90%) the conjugative transfer of plasmid RP4, a model broad-host-range plasmid, between Escherichia coli. The antimicrobial role of FNA at the applied dosages was firstly ruled out, since no dramatic reductions in viabilities of donor or recipient were observed. Instead, FNA appeared to reduce the available intracellular free Mg2+, which was confirmed to be triggered by the liberation of intracellular Fe2+. These alterations in intracellular Mg2+ and Fe2+ concentrations were found to significantly limit the available energy for conjugative transfer through suppression of glycolysis by decreasing the activities of glycogen phosphorylase and glyceraldehyde-3-phosphate dehydrogenase and also by diverting the glycolytic flux into the pentose phosphate pathway via activation of glucose-6-phosphate dehydrogenase towards the generation of NADPH rather than ATP. Moreover, RP4-encoding genes responsible for DNA transfer and replication (traI, traJ and trfAp), coupling (traG) and mating pair formation (traF and trbBp) were all significantly down-regulated after FNA treatment, indicating that the transfer apparatus required for plasmid processing and delivery was deactivated. By validating the inhibitory effects of FNA on conjugation in real wastewater, this study highlights a promising method for controlling the dissemination of ARGs in systems such as wastewater treatment plants.
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Affiliation(s)
- Haining Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Junqi Liao
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Xiong Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210093, Jiangsu, PR China
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