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Pan Y, Deng R, Jin C, Li Y, Ren B, Hou B, Wang C, Yang X, Hursthouse A. Isolation and Identification of Highly Sb-Resistant Rhodotorula glutinis Strain J5 and its Mechanism of Resistance to Sb(III). Curr Microbiol 2024; 81:335. [PMID: 39215822 DOI: 10.1007/s00284-024-03867-7] [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: 05/19/2024] [Accepted: 08/21/2024] [Indexed: 09/04/2024]
Abstract
Sb-resistant strains can detoxify antimony through metabolic mechanisms such as oxidation and affect the migration, transformation, and ultimate fate of antimony in the environment. In this study, a strain of Sb-resistant fungi, Rhodotorula glutinis sp. Strain J5, was isolated from Xikuangshan mine and its growth characteristics, gene expression differences, and functional annotation under Sb(III) stress were further investigated to reveal the mechanism of resistance to Sb(III). We identified strain J5 as belonging to the Rhodotorula glutinis species optimally growing at pH 5.0 and at 28 °C of temperature. According to gene annotation and differential expression, the resistance mechanism of Strain J5 includes: reducing the endocytosis of antimony by aquaporin AQP8 and transmembrane transporter pst, enhancing the efflux of Sb(III) by the gene expression of acr2, acr3 and ABC, improving the oxidation of Sb(III) by iron-sulfur protein and Superoxide dismutase (SOD), glutathione (GSH) and cysteine (Cys) chelation, methylation of methyltransferase and N-methyltransferase, accelerating cell damage repair and EPS synthesis and other biochemical reaction mechanisms. FT-IR analysis shows that the -OH, -COOH, -NH, -PO, C-O, and other active groups of Strain J5 can be complexed with Sb(III), resulting in chemical adsorption. Strain J5 displays significant resistance to Sb(III) with the MIC of 1300 mg/L, playing a crucial role in the global biochemical transformation of antimony and its potential application in soil microbial remediation.
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Affiliation(s)
- Yulin Pan
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Renjian Deng
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China.
| | - Changsheng Jin
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing, 312000, China
| | - Yinfu Li
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Bozhi Ren
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Baolin Hou
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Chuang Wang
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Xiuzhen Yang
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Andrew Hursthouse
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
- School of Computing, Engineering and Physical Sciences, University of the West of Scotland, Paisley, PA1 2BE, UK
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Xiao S, Wang M, Amanze C, Anaman R, Ssekimpi D, Zeng W. Mechanisms of adaptive resistance in Phytobacter sp. X4 to antimony stress under anaerobic conditions. JOURNAL OF HAZARDOUS MATERIALS 2024; 479:135628. [PMID: 39208624 DOI: 10.1016/j.jhazmat.2024.135628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 08/05/2024] [Accepted: 08/21/2024] [Indexed: 09/04/2024]
Abstract
Sb(III) oxidation by microorganisms plays a key role in the geochemical cycling of antimony and is effective for bioremediation. A previously discovered novel Sb(III)-oxidizing bacteria, Phytobacter sp. X4, was used to elucidate the response patterns of extracellular polypeptides (EPS), antioxidant system, electron transfer and functional genes to Sb(III) under anaerobic conditions. The toxicity of Sb(III) was mitigated by increasing Sb(III) oxidation capacity, and the EPS regulated the content of each component by sensing the concentration of Sb(III). High Sb(III) concentrations induced significant secretion of proteins and polysaccharides of EPS, and polysaccharides were more important. Functional groups including hydroxyl, carboxyl and amino groups on the cell surface adsorbed Sb(III) to block its entry. Hydroxyl radicals and hydrogen peroxide were involved in anaerobic Sb(III) oxidation, as revealed by changes in the antioxidant system and electron spin resonance (EPR) techniques. qPCR confirmed that proteins concerning nitrate and antimony transfer, antimony resistance and antioxidant system were regulated by Sb(III) concentration, and the synergistic cooperation of multiple proteins conferred high antimony resistance to X4. The adaptive antimony resistance mechanism of Phytobacter sp. X4 under anaerobic conditions was revealed, which also provides a reference value for bioremediation method of antimony contamination in anaerobic environment.
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Affiliation(s)
- Shanshan Xiao
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 China
| | - Mingwei Wang
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 China
| | - Charles Amanze
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 China
| | - Richmond Anaman
- School of Metallurgy and Environment, Central South University, Changsha 410083, China
| | - Dennis Ssekimpi
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL 32310, United States
| | - Weimin Zeng
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 China; Key Laboratory of Biometallurgy, Ministry of Education, Changsha 410083, China.
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Mettert EL, Kiley PJ. Fe-S cluster homeostasis and beyond: The multifaceted roles of IscR. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119749. [PMID: 38763301 PMCID: PMC11309008 DOI: 10.1016/j.bbamcr.2024.119749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 03/29/2024] [Accepted: 05/08/2024] [Indexed: 05/21/2024]
Abstract
The role of IscR in regulating the transcription of genes involved in Fe-S cluster homeostasis has been well established for the model organism Escherichia coli K12. In this bacterium, IscR coordinates expression of the Isc and Suf Fe-S cluster assembly pathways to meet cellular Fe-S cluster demands shaped by a variety of environmental cues. However, since its initial discovery nearly 25 years ago, there has been growing evidence that IscR function extends well beyond Fe-S cluster homeostasis, not only in E. coli, but in bacteria of diverse lifestyles. Notably, pathogenic bacteria have exploited the ability of IscR to respond to changes in oxygen tension, oxidative and nitrosative stress, and iron availability to navigate their trajectory in their respective hosts as changes in these cues are frequently encountered during host infection. In this review, we highlight these broader roles of IscR in different cellular processes and, in particular, discuss the importance of IscR as a virulence factor for many bacterial pathogens.
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Affiliation(s)
- Erin L Mettert
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Patricia J Kiley
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
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Zhang M, Xiong J, Zhou L, Li J, Fan J, Li X, Zhang T, Yin Z, Yin H, Liu X, Meng D. Community ecological study on the reduction of soil antimony bioavailability by SRB-based remediation technologies. JOURNAL OF HAZARDOUS MATERIALS 2023; 459:132256. [PMID: 37567138 DOI: 10.1016/j.jhazmat.2023.132256] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/27/2023] [Accepted: 08/07/2023] [Indexed: 08/13/2023]
Abstract
Sulfate-reducing bacteria (SRB) were effective in stabilizing Sb. However, the influence of electron donors and acceptors during SRB remediation, as well as the ecological principles involved, remained unclear. In this study, Desulfovibrio desulfuricans ATCC 7757 was utilized to stabilize soil Sb within microcosm. Humic acid (HA) or sodium sulfate (Na2SO4) were employed to enhance SRB capacity. The SRB+HA treatment exhibited the highest Sb stabilization rate, achieving 58.40%. Bacterial community analysis revealed that SRB altered soil bacterial diversity, community composition, and assembly processes, with homogeneous selection as the predominant assembly processes. When HA and Na2SO4 significantly modified the stimulated microbial community succession trajectories, shaped the taxonomic composition and interactions of the bacterial community, they showed converse effect in shaping bacterial community which were both helpful for promoting dissimilatory sulfate reduction. Na2SO4 facilitated SRB-mediated anaerobic reduction and promoted interactions between SRB and bacteria involved in nitrogen and sulfur cycling. The HA stimulated electron generation and storage, and enhanced the interactions between SRB and bacteria possessing heavy metal tolerance or carbohydrate degradation capabilities.
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Affiliation(s)
- Min Zhang
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key laboratory of Biometallurgy, Ministry of Education, Changsha 410083, China
| | - Jing Xiong
- Hunan urban and Rural Environmental Construction Co., Ltd, Changsha 410118, China
| | - Lei Zhou
- Beijing Research Institute of Chemical Engineering and Metallurgy, Beijing 101148, China
| | - Jingjing Li
- Technology Center, China Tobacco Fujian Industrial Co., Ltd., Xiamen, Fujian 361000, China
| | - Jianqiang Fan
- Technology Center, China Tobacco Fujian Industrial Co., Ltd., Xiamen, Fujian 361000, China
| | - Xing Li
- Hunan HIKEE Environmental Technology CO., LTD, Changsha 410221, China
| | - Teng Zhang
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Hunan urban and Rural Environmental Construction Co., Ltd, Changsha 410118, China; Key laboratory of Biometallurgy, Ministry of Education, Changsha 410083, China
| | - Zhuzhong Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key laboratory of Biometallurgy, Ministry of Education, Changsha 410083, China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key laboratory of Biometallurgy, Ministry of Education, Changsha 410083, China
| | - Xueduan Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key laboratory of Biometallurgy, Ministry of Education, Changsha 410083, China
| | - Delong Meng
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key laboratory of Biometallurgy, Ministry of Education, Changsha 410083, China.
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Luo X, Guo J, Lan Y, An L, Zhang X, Shi K, Zheng S, Li M. Toxic response of antimony in the Comamonas testosteroni and its application in soil antimony bioremediation. ENVIRONMENT INTERNATIONAL 2023; 178:108040. [PMID: 37356310 DOI: 10.1016/j.envint.2023.108040] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023]
Abstract
Antimony (Sb) is toxic to ecosystems and potentially to public health via its accumulation in the food chain. Bioavailability and toxicity of Sb have been reduced using various methods for the remediation of Sb-contaminated soil in most studies. However, Sb-contaminated soil remediation by microbial agents has been rarely evaluated. In this study, we evaluated the potential for the use of Comamonas testosteroni JL40 in the bioremediation of Sb-contamination. Strain JL40 immobilized more than 30 % of the Sb(III) in solution and oxidized over 18 % to Sb(V) for detoxification. Meanwhile, strain JL40 responds to Sb toxicity through such as Sb efflux, intracellular accumulation, biofilm production, and scavenging of reactive oxygen species (ROS), etc. The results of the pot experiment showed the average Sb content of the brown rice was decreased by 59.1%, 38.8%, and 48.4%, for 1.8, 50, and 100 mg/kg Sb spiked soils, respectively. In addition, the results of plant, soil enzyme activity, and rice agronomic trait observations showed that the application of strain JL40 could maintain the health of plants and soil and improve rice production. The single-step and sequential extraction of Sb from rhizosphere soil showed that strain JL40 also plays a role in Sb immobilization and oxidation in the soil environment. During rice potted cultivation, bacterial community analysis and plate counting showed that the strain JL40 could still maintain 103 CFU/g after 30 days of inoculation. With phenotypic and differential proteomics analysis, strain JL40 conferred Sb(III) tolerance by a combination of immobilization, oxidation, efflux and scavenging of ROS, etc. Our study demonstrates the application of Sb-immobilizing and oxidizing bacteria to lower soil Sb and reduce accumulation of Sb in rice. Our results provide guidance for bacterial remediation of Sb-contaminated soil.
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Affiliation(s)
- Xiong Luo
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Jiayi Guo
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Yan Lan
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Lijin An
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Xiaoyan Zhang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Kaixiang Shi
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Shixue Zheng
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Mingshun Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
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Wu Y, Xiang L, Wang H, Ma L, Qiu X, Liu D, Feng L, Lu X. Transcriptome analysis of an arsenite-/antimonite-oxidizer, Bosea sp. AS-1 reveals the importance of the type 4 secretion system in antimony resistance. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 826:154168. [PMID: 35231521 DOI: 10.1016/j.scitotenv.2022.154168] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
Bosea sp. AS-1 is an arsenite [As(III)] and antimonite [Sb(III)] oxidizer previously isolated by our group from the Xikuangshan Antimony (Sb) Mine area. Our previous study showed that Bosea sp. AS-1 had a preference for oxidizing As(III) or Sb(III) with different carbon sources, which suggested that different metabolic mechanisms may be utilized by the bacteria to survive in As(III)- or Sb(III)-contaminated environments. Here, we conducted whole-genome and transcriptome sequencing to reveal the molecular mechanisms utilized by Bosea sp. AS-1 to resist As(III) or Sb(III). We discovered that AS-1 acquired various As- and Sb-resistant genes in its genome and might resist As(III) or Sb(III) through the regulation of multiple pathways, such as As and Sb metabolism, the bacterial secretion system, oxidative phosphorylation, the TCA cycle and bacterial flagellar motility. Interestingly, we discovered that genes of the type IV secretion system (T4SS) were activated in response to Sb(III), and inhibiting T4SS activity in AS-1 dramatically reduced its oxidation efficiency and tolerance to Sb(III). To our knowledge, this is the first study showing the activation of T4SS genes by Sb and a direct involvement of T4SS in bacterial Sb resistance. Our findings establish the T4SS as an important Sb resistance factor in bacteria and may help us understand the spread of Sb resistance genes in the environment.
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Affiliation(s)
- Yanmei Wu
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Li Xiang
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Hongmei Wang
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China; State Key Laboratory of Biogeology and Environmental Geology, China University of China (Wuhan), Wuhan 430074, China
| | - Liyuan Ma
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Xuan Qiu
- State Key Laboratory of Biogeology and Environmental Geology, China University of China (Wuhan), Wuhan 430074, China
| | - Deng Liu
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Liang Feng
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Xiaolu Lu
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China.
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7
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Rong Q, Ling C, Lu D, Zhang C, Zhao H, Zhong K, Nong X, Qin X. Sb(III) resistance mechanism and oxidation characteristics of Klebsiella aerogenes X. CHEMOSPHERE 2022; 293:133453. [PMID: 34971630 DOI: 10.1016/j.chemosphere.2021.133453] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 12/15/2021] [Accepted: 12/25/2021] [Indexed: 06/14/2023]
Abstract
Resistant bacteria are potential natural materials for the bioremediation of soil metalloid pollution. A strain isolated from farmland soil chronically exposed to Sb was identified as K. aerogenes X with high antimonite [Sb(III)] tolerance and oxidation ability. The resistance mechanism of K. aerogenes X and its extracellular polymeric substances (EPS), antioxidant enzymes, and oxidation characteristics in Sb(III) stress were investigated in this study by stress incubation experiments and FTIR. The biotoxicity of Sb was limited by the binding of the organic compounds in EPS, and the anionic functional groups (e.g., amino, carboxyl and hydroxyl groups, etc.) present in the cell envelope were the components primarily responsible for the metalloid-binding capability of K. aerogenes X. The K. aerogenes X can oxidize Sb(III), and its metabolites induce changes in reactive oxygen species (ROS), catalase (CAT), total superoxide dismutase (SOD) and glutathione s-transferase (GSH-S) activity, indicating that the resistance mechanisms of K. aerogenes X are mediated by oxidative stress, EPS restriction and cell damage. Oxidation of Sb(III) is driven by interactions in intracellular oxidation, cell electron transport, extracellular metabolism including proteins and low molecular weight components (LMWs). LMWs (molecular weight <3 kDa) are the main driving factor of Sb(III) oxidation. In addition, Sb resistance genes arsA, arsB, arsC, arsD and acr3 and potential oxidation gene arsH were identified in K. aerogenes X. Owing to its natural origin, high tolerance and oxidation ability, K. aerogenes X could serve as a potential bioremediation material for the mitigation of Sb(III) in contaminated areas.
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Affiliation(s)
- Qun Rong
- College of Life Science and Technology GuangXi University, Nanning, PR China
| | - Caiyuan Ling
- College of Resources, Environment and Materials GuangXi University, Nanning, PR China
| | - Dingtian Lu
- College of Resources, Environment and Materials GuangXi University, Nanning, PR China
| | - Chaolan Zhang
- College of Resources, Environment and Materials GuangXi University, Nanning, PR China.
| | - Hecheng Zhao
- College of Resources, Environment and Materials GuangXi University, Nanning, PR China
| | - Kai Zhong
- College of Resources, Environment and Materials GuangXi University, Nanning, PR China
| | - Xinyu Nong
- College of Resources, Environment and Materials GuangXi University, Nanning, PR China
| | - Xingzi Qin
- College of Resources, Environment and Materials GuangXi University, Nanning, PR China
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Deng R, Chen Y, Deng X, Huang Z, Zhou S, Ren B, Jin G, Hursthouse A. A Critical Review of Resistance and Oxidation Mechanisms of Sb-Oxidizing Bacteria for the Bioremediation of Sb(III) Pollution. Front Microbiol 2021; 12:738596. [PMID: 34557178 PMCID: PMC8453088 DOI: 10.3389/fmicb.2021.738596] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 07/30/2021] [Indexed: 12/03/2022] Open
Abstract
Antimony (Sb) is a priority pollutant in many countries and regions due to its chronic toxicity and potential carcinogenicity. Elevated concentrations of Sb in the environmental originating from mining and other anthropogenic sources are of particular global concern, so the prevention and control of the source of pollution and environment remediation are urgent. It is widely accepted that indigenous microbes play an important role in Sb speciation, mobility, bioavailability, and fate in the natural environment. Especially, antimony-oxidizing bacteria can promote the release of antimony from ore deposits to the wider environment. However, it can also oxidize the more toxic antimonite [Sb(III)] to the less-toxic antimonate [Sb(V)], which is considered as a potentially environmentally friendly and efficient remediation technology for Sb pollution. Therefore, understanding its biological oxidation mechanism has great practical significance to protect environment and human health. This paper reviews studies of the isolation, identification, diversity, Sb(III) resistance mechanisms, Sb(III) oxidation characteristics and mechanism and potential application of Sb-oxidizing bacteria. The aim is to provide a theoretical basis and reference for the diversity and metabolic mechanism of Sb-oxidizing bacteria, the prevention and control of Sb pollution sources, and the application of environment treatment for Sb pollution.
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Affiliation(s)
- Renjian Deng
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, China
| | - Yilin Chen
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, China
| | - Xinpin Deng
- Hunan 402 Geological Prospecting Part, Changsha, China
| | - Zhongjie Huang
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, China
| | - Saijun Zhou
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, China
| | - Bozhi Ren
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, China
| | - Guizhong Jin
- Hsikwangshan Twinkling Star Co., Ltd., Lengshuijiang, China
| | - Andrew Hursthouse
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, China
- School of Computing, Engineering and Physical Sciences, The University of the West of Scotland, Paisley, United Kingdom
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9
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Nonoyama S, Kishida K, Sakai K, Nagata Y, Ohtsubo Y, Tsuda M. A transcriptional regulator, IscR, of Burkholderia multivorans acts as both repressor and activator for transcription of iron-sulfur cluster-biosynthetic isc operon. Res Microbiol 2020; 171:319-330. [PMID: 32628999 DOI: 10.1016/j.resmic.2020.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/26/2020] [Indexed: 11/18/2022]
Abstract
Bacterial iron-sulfur (Fe-S) clusters are essential cofactors for many metabolic pathways, and Fe-S cluster-containing proteins (Fe-S proteins) regulate the expression of various important genes. However, biosynthesis of such clusters has remained unknown in genus Burkholderia. Here, we clarified that Burkholderia multivorans ATCC 17616 relies on the ISC system for the biosynthesis of Fe-S clusters, and that the biosynthetic genes are organized as an isc operon, whose first gene encodes IscR, a transcriptional regulatory Fe-S protein. Transcription of the isc operon was repressed and activated under iron-rich and -limiting conditions, respectively, and Fur, an iron-responsive global transcriptional regulator, was indicated to indirectly regulate the expression of isc operon. Further analysis using a ΔiscR mutant in combination with a constitutive expression system of IscR and its derivatives indicated transcriptional repression and activation of isc operon by holo- and apo-forms of IscR, respectively, through their binding to the sequences within an isc promoter-containing (Pisc) fragment. Biochemical analysis using the Pisc fragment suggested that the apo-IscR binding sequence differs from the holo-IscR binding sequence. The results obtained in this study revealed a unique regulatory system for the expression of the ATCC 17616 isc operon that has not been observed in other genera.
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Affiliation(s)
- Shouta Nonoyama
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan.
| | - Kouhei Kishida
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan.
| | - Keiichiro Sakai
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan.
| | - Yuji Nagata
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan.
| | - Yoshiyuki Ohtsubo
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan.
| | - Masataka Tsuda
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan.
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Xia X, Wu S, Li L, Xu B, Wang G. The Cytochrome bd Complex Is Essential for Chromate and Sulfide Resistance and Is Regulated by a GbsR-Type Regulator, CydE, in Alishewanella Sp. WH16-1. Front Microbiol 2018; 9:1849. [PMID: 30147685 PMCID: PMC6096048 DOI: 10.3389/fmicb.2018.01849] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 07/24/2018] [Indexed: 01/17/2023] Open
Abstract
Sulfate-reducing bacteria are a group of microorganisms that use sulfate as an electron acceptor. These bacteria are useful in the bioremediation of heavy metal pollution since they can reduce/precipitate metals. Previously, we identified the Alishewanella strain WH16-1 from soil of a copper and iron mine and determined that it can reduce sulfate and chromate and that it was tolerant to many heavy metals. In this study, we investigated the chromate reduction mechanism of strain WH16-1 through Tn5 transposon mutagenesis. A cytochrome bd (cytbd) Tn5 mutant was generated (Δcytbd), and a detail analysis showed that the following: (1) gene cydE (coding for a GbsR-type regulator) was co-transcribed with the two subunits coding genes of the Cytochrome bd complex (Cytbd), namely, cydA and cydB, based on RT-PCR analysis, and similar gene arrangements were also found in other Alteromonadaceae family strains; (2) the chromate resistance level was dramatically decreased and chromate reduction efficiency also decreased in strain Δcytbd compared to the wild-type and a complemented strain (Δcytbd-C); (3) Cytbd could catalyze the decomposition of H2O2 according to the analyses of H2O2 decomposition ability, cellular H2O2 contents, H2O2 inhibition zone, and H2O2 sensitivity tests; (4) surprisingly, chromate was not an inducer of the expression of Cytbd, but sulfate induced expression of Cytbd, and sulfate/sulfide resistance levels were also decreased in the Δcytbd strain; (5) the addition of sulfate enhanced the chromate resistance level and reduction efficiency; (6) Cytbd expression was repressed by CydE and derepressed by sulfate based on an in vivo bacterial one hybrid system and in vitro EMSA tests; and (7) DNA footprinting and short-fragment EMSA tests revealed two binding sites of CydE in its promoter region. All these results showed that Cytbd is negatively regulated by CydE and derepressed by sulfate. In addition, Cytbd contributes to the resistance of sulfate and sulfide, and sulfide could be used as a reductant to reduce chromate. Moreover, Cytbd is essential to decompose H2O2 to decrease cellular oxidative stress. Thus, the regulation and function of Cytbd may explain why sulfate could enhance chromate reduction.
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Affiliation(s)
- Xian Xia
- State Key Laboratory of Agricultural Microbiology, College of Life Sciences and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shijuan Wu
- State Key Laboratory of Agricultural Microbiology, College of Life Sciences and Technology, Huazhong Agricultural University, Wuhan, China
| | - Liqiong Li
- State Key Laboratory of Agricultural Microbiology, College of Life Sciences and Technology, Huazhong Agricultural University, Wuhan, China
| | - Biao Xu
- State Key Laboratory of Agricultural Microbiology, College of Life Sciences and Technology, Huazhong Agricultural University, Wuhan, China
| | - Gejiao Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Sciences and Technology, Huazhong Agricultural University, Wuhan, China
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Pseudomonas aeruginosa nfuA: Gene regulation and its physiological roles in sustaining growth under stress and anaerobic conditions and maintaining bacterial virulence. PLoS One 2018; 13:e0202151. [PMID: 30092083 PMCID: PMC6084964 DOI: 10.1371/journal.pone.0202151] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/27/2018] [Indexed: 11/19/2022] Open
Abstract
The role of the nfuA gene encoding an iron-sulfur ([Fe-S]) cluster-delivery protein in the pathogenic bacterium Pseudomonas aeruginosa was investigated. The analysis of nfuA expression under various stress conditions showed that superoxide generators, a thiol-depleting agent and CuCl2 highly induced nfuA expression. The expression of nfuA was regulated by a global [2Fe-2S] cluster containing the transcription regulator IscR. Increased expression of nfuA in the ΔiscR mutant under uninduced conditions suggests that IscR acts as a transcriptional repressor. In vitro experiments revealed that IscR directly bound to a sequence homologous to the Escherichia coli Type-I IscR-binding motifs on a putative nfuA promoter that overlapped the -35 element. Binding of IscR prevented RNA polymerase from binding to the nfuA promoter, leading to repression of the nfuA transcription. Physiologically, deletion of nfuA reduced the bacterial ability to cope with oxidative stress, iron deprivation conditions and attenuated virulence in the Caenorhabditis elegans infection model. Site-directed mutagenesis analysis revealed that the conserved CXXC motif of the Nfu-type scaffold protein domain at the N-terminus was required for the NfuA functions in conferring the stress resistance phenotype. Furthermore, anaerobic growth of the ΔnfuA mutant in the presence of nitrate was drastically retarded. This phenotype was associated with a reduction in the [Fe-S] cluster containing nitrate reductase enzyme activity. However, NfuA was not required for the maturation of [Fe-S]-containing proteins such as aconitase, succinate dehydrogenase, SoxR and IscR. Taken together, our results indicate that NfuA functions in [Fe-S] cluster delivery to selected target proteins that link to many physiological processes such as anaerobic growth, bacterial virulence and stress responses in P. aeruginosa.
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Shi K, Wang Q, Fan X, Wang G. Proteomics and genetic analyses reveal the effects of arsenite oxidation on metabolic pathways and the roles of AioR in Agrobacterium tumefaciens GW4. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 235:700-709. [PMID: 29339339 DOI: 10.1016/j.envpol.2018.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 01/02/2018] [Accepted: 01/02/2018] [Indexed: 06/07/2023]
Abstract
A heterotrophic arsenite [As(III)]-oxidizing bacterium Agrobacterium tumefaciens GW4 isolated from As(III)-rich groundwater sediment showed high As(III) resistance and could oxidize As(III) to As(V). The As(III) oxidation could generate energy and enhance growth, and AioR was the regulator for As(III) oxidase. To determine the related metabolic pathways mediated by As(III) oxidation and whether AioR regulated other cellular responses to As(III), isobaric tags for relative and absolute quantitation (iTRAQ) was performed in four treatments, GW4 (+AsIII)/GW4 (-AsIII), GW4-ΔaioR (+AsIII)/GW4-ΔaioR (-AsIII), GW4-ΔaioR (-AsIII)/GW4 (-AsIII) and GW4-ΔaioR (+AsIII)/GW4 (+AsIII). A total of 41, 71, 82 and 168 differentially expressed proteins were identified, respectively. Using electrophoretic mobility shift assay (EMSA) and qRT-PCR, 12 genes/operons were found to interact with AioR. These results indicate that As(III) oxidation alters several cellular processes related to arsenite, such as As resistance (ars operon), phosphate (Pi) metabolism (pst/pho system), TCA cycle, cell wall/membrane, amino acid metabolism and motility/chemotaxis. In the wild type with As(III), TCA cycle flow is perturbed, and As(III) oxidation and fermentation are the main energy resources. However, when strain GW4-ΔaioR lost the ability of As(III) oxidation, the TCA cycle is the main way to generate energy. A regulatory cellular network controlled by AioR is constructed and shows that AioR is the main regulator for As(III) oxidation, besides, several other functions related to As(III) are regulated by AioR in parallel.
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Affiliation(s)
- Kaixiang Shi
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Qian Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Xia Fan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Gejiao Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China.
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Zhuang W, Liu H, Li J, Chen L, Wang G. Regulation of Class A β-Lactamase CzoA by CzoR and IscR in Comamonas testosteroni S44. Front Microbiol 2017; 8:2573. [PMID: 29312251 PMCID: PMC5744064 DOI: 10.3389/fmicb.2017.02573] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 12/11/2017] [Indexed: 11/13/2022] Open
Abstract
A genomic analysis of Comamonas testosteroni S44 revealed a gene that encodes a LysR family transcriptional regulator (here named czoR, czo for cefazolin) located upstream of a putative class A β-lactamase encoding gene (here named czoA). A putative DNA-binding motif of the Fe-S cluster assembly regulator IscR was identified in the czoR-czoA intergenic region. Real-time RT-PCR and lacZ fusion expression assays indicated that transcription of czoA and czoR were induced by multiple β-lactams. CzoA expressed in Escherichia coli was shown to contribute to susceptibility to a wide range of β-lactams judged from minimum inhibitory concentrations. In vitro enzymatic assays showed that CzoA hydrolyzed seven β-lactams, including benzylpenicillin, ampicillin, cefalexin, cefazolin, cefuroxime, ceftriaxone, and cefepime. Deletion of either iscR or czoR increased susceptibility to cefalexin and cefazolin, while complemented strains restored their wild-type susceptibility levels. Electrophoretic mobility shift assays (EMSA) demonstrated that CzoR and IscR bind to different sites of the czoR-czoA intergenic region. Precise CzoR- and IscR-binding sites were confirmed via DNase I footprinting or short fragment EMSA. When cefalexin or cefazolin was added to cultures, czoR deletion completely inhibited czoA expression but did not affect iscR transcription, while iscR deletion decreased the expressions of both czoR and czoA. These results reveal that CzoR positively affects the expression of czoA with its own expression upregulated by IscR.
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Affiliation(s)
- Weiping Zhuang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Hongliang Liu
- Shandong Provincial Research Center for Bioinformatic Engineering and Technique, School of Life Sciences, Shandong University of Technology, Zibo, China
| | - Jingxin Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Lu Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Gejiao Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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Microbial Antimony Biogeochemistry: Enzymes, Regulation, and Related Metabolic Pathways. Appl Environ Microbiol 2016; 82:5482-95. [PMID: 27342551 DOI: 10.1128/aem.01375-16] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimony (Sb) is a toxic metalloid that occurs widely at trace concentrations in soil, aquatic systems, and the atmosphere. Nowadays, with the development of its new industrial applications and the corresponding expansion of antimony mining activities, the phenomenon of antimony pollution has become an increasingly serious concern. In recent years, research interest in Sb has been growing and reflects a fundamental scientific concern regarding Sb in the environment. In this review, we summarize the recent research on bacterial antimony transformations, especially those regarding antimony uptake, efflux, antimonite oxidation, and antimonate reduction. We conclude that our current understanding of antimony biochemistry and biogeochemistry is roughly equivalent to where that of arsenic was some 20 years ago. This portends the possibility of future discoveries with regard to the ability of microorganisms to conserve energy for their growth from antimony redox reactions and the isolation of new species of "antimonotrophs."
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