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Kerdsomboon K, Techo T, Mhuantong W, Limcharoensuk T, Luangkamchorn ST, Laoburin P, Auesukaree C. Genomic and transcriptomic analyses reveal insights into cadmium resistance mechanisms of Cupriavidus nantongensis strain E324. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 952:175915. [PMID: 39216765 DOI: 10.1016/j.scitotenv.2024.175915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Revised: 08/14/2024] [Accepted: 08/29/2024] [Indexed: 09/04/2024]
Abstract
The cadmium-resistant Cupriavidus sp. strain E324 has been previously shown to have a high potential for use in cadmium (Cd) remediation, due to its high capacity for cadmium bioaccumulation. According to the comparative genomic analysis, the strain E324 was most closely related to C. nantongensis X1T, indicating that the strain E324 should be re-identified as C. nantongensis. To unravel the Cd tolerance mechanisms of C. nantongensis strain E324, the transcriptional response of this strain to acute Cd exposure was assessed using RNA-seq-based transcriptome analysis, followed by validation through qRT-PCR. The results showed that the upregulated Differentially Expressed Genes (DEGs) were significantly enriched in categories related to metal binding and transport, phosphate transport, and oxidative stress response. Consistently, we observed significant increases in both the cell wall and intracellular contents of certain essential metals (Cu, Fe, Mn, and Zn) upon Cd exposure. Among these, only the Zn pretreatment resulting in high Zn accumulation in the cell walls could enhance bacterial growth under Cd stress conditions through its role in inhibiting Cd accumulation. Additionally, the promotion of catalase activity and glutathione metabolism upon Cd exposure to cope with Cd-induced oxidative stress was demonstrated. Meanwhile, the upregulation of phosphate transport-related genes upon Cd treatment seems to be the bacterial response to Cd-induced phosphate depletion. Altogether, our findings suggest that these adaptive responses are critical mechanisms contributing to increased Cd tolerance in C. nantongensis strain E324 via the enhancement of metal-chelating and antioxidant capacities of the cells.
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Affiliation(s)
- Kittikhun Kerdsomboon
- Chulabhorn International College of Medicine, Thammasat University, Pathum Thani 12120, Thailand; Mahidol University-Osaka University Collaborative Research Center for Bioscience and Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Todsapol Techo
- Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Wuttichai Mhuantong
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Thailand Science Park, Pathum Thani 12120, Thailand
| | - Tossapol Limcharoensuk
- Mahidol University-Osaka University Collaborative Research Center for Bioscience and Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Supinda Tatip Luangkamchorn
- Mahidol University-Osaka University Collaborative Research Center for Bioscience and Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Analytical Sciences and National Doping Test Institute, Mahidol University, Bangkok 10400, Thailand
| | - Patcharee Laoburin
- Mahidol University-Osaka University Collaborative Research Center for Bioscience and Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Choowong Auesukaree
- Mahidol University-Osaka University Collaborative Research Center for Bioscience and Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
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Roberts CS, Shannon AB, Korotkov KV, Sandkvist M. Differential processing of VesB by two rhomboid proteases in Vibrio cholerae. mBio 2024:e0127024. [PMID: 39136457 DOI: 10.1128/mbio.01270-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/08/2024] [Indexed: 08/21/2024] Open
Abstract
Rhomboid proteases are universally conserved and facilitate the proteolysis of peptide bonds within or adjacent to cell membranes. While eukaryotic rhomboid proteases have been demonstrated to harbor unique cellular roles, prokaryotic members have been far less characterized. For the first time, we demonstrate that Vibrio cholerae expresses two active rhomboid proteases that cleave a shared substrate at distinct sites, resulting in differential localization of the processed protein. The rhomboid protease rhombosortase (RssP) was previously found to process a novel C-terminal domain called GlyGly-CTERM, as demonstrated by its effect on the extracellular serine protease VesB during its transport through the V. cholerae cell envelope. Here, we characterize the substrate specificity of RssP and GlpG, the universally conserved bacterial rhomboid proteases. We show that RssP has distinct cleavage specificity from GlpG, and specific residues within the GlyGly-CTERM of VesB target it to RssP over GlpG, allowing for efficient proteolysis. RssP cleaves VesB within its transmembrane domain, whereas GlpG cleaves outside the membrane in a disordered loop that precedes the GlyGly-CTERM. Cleavage of VesB by RssP initially targets VesB to the bacterial cell surface and, subsequently, to outer membrane vesicles, while GlpG cleavage results in secreted, fully soluble VesB. Collectively, this work builds on the molecular understanding of rhomboid proteolysis and provides the basis for additional rhomboid substrate recognition while also demonstrating a unique role of RssP in the maturation of proteins containing a GlyGly-CTERM. IMPORTANCE Despite a great deal of insight into the eukaryotic homologs, bacterial rhomboid proteases have been relatively understudied. Our research aims to understand the function of two rhomboid proteases in Vibrio cholerae. This work is significant because it will help us better understand the catalytic mechanism of rhomboid proteases as a whole and assign a specific role to a unique subfamily whose function is to process a subset of effector molecules secreted by V. cholerae and other pathogenic bacteria.
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Affiliation(s)
- Cameron S Roberts
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Austin B Shannon
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Konstantin V Korotkov
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Maria Sandkvist
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Khan MTA, Al-Battashi H, Al-Hinai M, Almdawi M, Pracejus B, Elshafey ESI, Abed RMM. Isolation of Aerobic Heterotrophic Bacteria from a Microbial Mat with the Ability to Grow on and Remove Hexavalent Chromium through Biosorption and Bioreduction. Appl Biochem Biotechnol 2024:10.1007/s12010-024-05023-0. [PMID: 39102082 DOI: 10.1007/s12010-024-05023-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2024] [Indexed: 08/06/2024]
Abstract
Water pollution with toxic hexavalent chromium, Cr(VI), is an environmental threat that has a direct impact on living organisms. The use of microorganisms from microbial mats to remove Cr(VI) has scarcely been investigated. Here, we isolated aerobic heterotrophic bacteria from a Cr-polluted microbial mat found in a mining site in Oman, and investigated their ability to remove Cr(VI), and the underlying mechanism(s) of removal. All isolates fell phylogenetically into the genera Enterobacter, Bacillus, and Cupriavidus, and could completely remove 1 mg L-1 Cr(VI) in 6 days. The strains could tolerate up to 2000 mg L-1 Cr(VI), and exhibited the highest Cr(VI) removal rate at 100 ± 9 mg L-1 d-1. Using scanning electron microscopy (SEM) coupled with elemental analysis, the strains were shown to adsorb Cr(VI) at their cell surfaces. The functional groups OH, NH2, Alkyl, Metal-O, and Cr(VI)-O were involved in the biosorption process. In addition, the strains were shown to reduce Cr(VI) to Cr(III) with the involvement of chromate reductase enzyme. We conclude that the aerobic heterotrophic bacteria isolated from Cr-polluted microbial mats use biosorption and bioreduction processes to remove Cr(VI) from wastewater.
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Affiliation(s)
- Mohammad Tariq Ali Khan
- Biology Department, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman
| | - Huda Al-Battashi
- Biology Department, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman
| | - Mahmood Al-Hinai
- Biology Department, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman
| | - Malak Almdawi
- Biology Department, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman
| | - Bernhard Pracejus
- Department of Earth Sciences, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman
| | - El-Said I Elshafey
- Chemistry Department, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman
| | - Raeid M M Abed
- Biology Department, College of Science, Sultan Qaboos University, P. O. Box: 36, PC 123, Al Khoud, Sultanate of Oman.
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Golubev S, Rasterkovskaya M, Sungurtseva I, Burov A, Muratova A. Phenanthrene-Degrading and Nickel-Resistant Neorhizobium Strain Isolated from Hydrocarbon-Contaminated Rhizosphere of Medicago sativa L. Microorganisms 2024; 12:1586. [PMID: 39203428 PMCID: PMC11356111 DOI: 10.3390/microorganisms12081586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2024] [Revised: 07/24/2024] [Accepted: 08/01/2024] [Indexed: 09/03/2024] Open
Abstract
Pollutant degradation and heavy-metal resistance may be important features of the rhizobia, making them promising agents for environment cleanup biotechnology. The degradation of phenanthrene, a three-ring polycyclic aromatic hydrocarbon (PAH), by the rhizobial strain Rsf11 isolated from the oil-polluted rhizosphere of alfalfa and the influence of nickel ions on this process were studied. On the basis of whole-genome and polyphasic taxonomy, the bacterium Rsf11 represent a novel species of the genus Neorhizobium, so the name Neorhizobium phenanthreniclasticum sp. nov. was proposed. Analysis of phenanthrene degradation by the Rsf1 strain revealed 1-hydroxy-2-naphthoic acid as the key intermediate and the activity of two enzymes apparently involved in PAH degradation. It was also shown that the nickel resistance of Rsf11 was connected with the extracellular adsorption of metal by EPS. The joint presence of phenanthrene and nickel in the medium reduced the degradation of PAH by the microorganism, apparently due to the inhibition of microbial growth but not due to the inhibition of the activity of the PAH degradation enzymes. Genes potentially involved in PAH catabolism and nickel resistance were discovered in the microorganism studied. N. phenanthreniclasticum strain Rsf11 can be considered as a promising candidate for use in the bioremediation of mixed PAH-heavy-metal contamination.
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Affiliation(s)
| | | | | | | | - Anna Muratova
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS), Saratov 410049, Russia; (S.G.); (M.R.); (I.S.); (A.B.)
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Xu Q, Ali S, Afzal M, Nizami AS, Han S, Dar MA, Zhu D. Advancements in bacterial chemotaxis: Utilizing the navigational intelligence of bacteria and its practical applications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 931:172967. [PMID: 38705297 DOI: 10.1016/j.scitotenv.2024.172967] [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: 02/15/2024] [Revised: 04/06/2024] [Accepted: 05/01/2024] [Indexed: 05/07/2024]
Abstract
The fascinating world of microscopic life unveils a captivating spectacle as bacteria effortlessly maneuver through their surroundings with astonishing accuracy, guided by the intricate mechanism of chemotaxis. This review explores the complex mechanisms behind this behavior, analyzing the flagellum as the driving force and unraveling the intricate signaling pathways that govern its movement. We delve into the hidden costs and benefits of this intricate skill, analyzing its potential to propagate antibiotic resistance gene while shedding light on its vital role in plant colonization and beneficial symbiosis. We explore the realm of human intervention, considering strategies to manipulate bacterial chemotaxis for various applications, including nutrient cycling, algal bloom and biofilm formation. This review explores the wide range of applications for bacterial capabilities, from targeted drug delivery in medicine to bioremediation and disease control in the environment. Ultimately, through unraveling the intricacies of bacterial movement, we can enhance our comprehension of the intricate web of life on our planet. This knowledge opens up avenues for progress in fields such as medicine, agriculture, and environmental conservation.
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Affiliation(s)
- Qi Xu
- International Joint Laboratory on Synthetic Biology and Biomass Biorefinery, Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Shehbaz Ali
- International Joint Laboratory on Synthetic Biology and Biomass Biorefinery, Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, PR China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, PR China
| | - Muhammad Afzal
- Soil & Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
| | - Abdul-Sattar Nizami
- Sustainable Development Study Centre, Government College University, Lahore 54000, Pakistan
| | - Song Han
- Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, PR China
| | - Mudasir A Dar
- International Joint Laboratory on Synthetic Biology and Biomass Biorefinery, Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Daochen Zhu
- International Joint Laboratory on Synthetic Biology and Biomass Biorefinery, Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, PR China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, PR China.
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Sun S, Wang Y, He B, Chen J, Leng F, Luo W. Comparative transcriptomics revealed the mechanism of Stenotrophomonas rhizophila JC1 response and biosorption to Pb 2. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2024; 46:231. [PMID: 38849682 DOI: 10.1007/s10653-024-02019-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 04/29/2024] [Indexed: 06/09/2024]
Abstract
Nowadays, there is limited research focusing on the biosorption of Pb2+ through microbial process, particularly at the level of gene expression. To overcome this knowledge gap, we studied the adsorption capacity of Stenotrophomonas rhizophila JC1 to Pb2+, and investigated the physiological mechanism by means of SEM, EDS, FTIR, membrane permeability detection, and investigated the molecular mechanism through comparative transcriptomics. The results showed that after 16 h of cultivation, the biosorption capacity of JC1 for 100 mg/L of Pb2+ reached at 79.8%. The main mechanism of JC1 adsorb Pb2+ is via intracellular accumulation, accounting for more than 90% of the total adsorption. At the physiological level, Pb2+ can precipitate with anion functional groups (e.g., -OH, -NH) on the bacterial cell wall or undergo replacement reaction with cell component elements (e.g., Si, Ca) to adsorb Pb2+ outside of the cell wall, thus accomplishing extracellular adsorption of Pb2+ by strains. Furthermore, the cell membrane acts as a "switch" that inhibits the entry of metal ions into the cell from the plasma membrane. At the molecular level, the gene pbt specificity is responsible for the adsorption of Pb2+ by JC1. In addition, phosphate permease is a major member of the ABC transporter family involved in Pb2+, and czcA/cusA or Co2+/Mg2+ efflux protein plays an important role in the efflux of Pb2+ in JC1. Further, cellular macromolecule biosynthesis, inorganic cation transmembrane transport, citrate cycle (TCA) and carbon metabolism pathways all play crucial roles in the response of strain JC1 to Pb2+ stress.
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Affiliation(s)
- Shangchen Sun
- Yellow River Basin Ecotope Integration of Industry and Education Research Institute, Lanzhou Resources & Environment Voc-Tech University, Lanzhou, 730030, China
| | - Yonggang Wang
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, Lanzhou, 730050, China.
| | - Bihong He
- Yellow River Basin Ecotope Integration of Industry and Education Research Institute, Lanzhou Resources & Environment Voc-Tech University, Lanzhou, 730030, China
| | - Jixiang Chen
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, 730050, China
| | - Feifan Leng
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, Lanzhou, 730050, China
| | - Wen Luo
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, Lanzhou, 730050, China
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Kwiatos N, Waldron KJ. In a state of flux: new insight into the transport processes that maintain bacterial metal homeostasis. J Bacteriol 2024; 206:e0014624. [PMID: 38712925 PMCID: PMC11112988 DOI: 10.1128/jb.00146-24] [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] [Indexed: 05/08/2024] Open
Abstract
A new study by Nies et al. (J Bacteriol 206:e00080-24, 2024, https://doi.org/10.1128/jb.00080-24) provides a rich, quantitative data set of zinc accumulation by cells of Cupriavidus metallidurans, including of mutant bacterial strains lacking import or efflux genes, and comparison of zinc accumulation by cells previously starved of metal with those of zinc-replete cells. The data surprisingly demonstrate the concomitant activity of both active metal import and metal efflux systems. They present a flow equilibrium model to describe zinc homeostasis in bacteria.
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Affiliation(s)
- Natalia Kwiatos
- Laboratory of Metalloprotein Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Kevin J. Waldron
- Laboratory of Metalloprotein Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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Halema AA, El-Beltagi HS, Al-Dossary O, Alsubaie B, Henawy AR, Rezk AA, Almutairi HH, Mohamed AA, Elarabi NI, Abdelhadi AA. Omics technology draws a comprehensive heavy metal resistance strategy in bacteria. World J Microbiol Biotechnol 2024; 40:193. [PMID: 38709343 DOI: 10.1007/s11274-024-04005-y] [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: 03/21/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024]
Abstract
The rapid industrial revolution significantly increased heavy metal pollution, becoming a major global environmental concern. This pollution is considered as one of the most harmful and toxic threats to all environmental components (air, soil, water, animals, and plants until reaching to human). Therefore, scientists try to find a promising and eco-friendly technique to solve this problem i.e., bacterial bioremediation. Various heavy metal resistance mechanisms were reported. Omics technologies can significantly improve our understanding of heavy metal resistant bacteria and their communities. They are a potent tool for investigating the adaptation processes of microbes in severe conditions. These omics methods provide unique benefits for investigating metabolic alterations, microbial diversity, and mechanisms of resistance of individual strains or communities to harsh conditions. Starting with genome sequencing which provides us with complete and comprehensive insight into the resistance mechanism of heavy metal resistant bacteria. Moreover, genome sequencing facilitates the opportunities to identify specific metal resistance genes, operons, and regulatory elements in the genomes of individual bacteria, understand the genetic mechanisms and variations responsible for heavy metal resistance within and between bacterial species in addition to the transcriptome, proteome that obtain the real expressed genes. Moreover, at the community level, metagenome, meta transcriptome and meta proteome participate in understanding the microbial interactive network potentially novel metabolic pathways, enzymes and gene species can all be found using these methods. This review presents the state of the art and anticipated developments in the use of omics technologies in the investigation of microbes used for heavy metal bioremediation.
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Affiliation(s)
- Asmaa A Halema
- Genetics Department, Faculty of Agriculture, Cairo University, Giza, 12613, Egypt
| | - Hossam S El-Beltagi
- Agricultural Biotechnology Department, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa, 31982, Saudi Arabia.
- Biochemistry Department, Faculty of Agriculture, Cairo University, Giza, 12613, Egypt.
| | - Othman Al-Dossary
- Agricultural Biotechnology Department, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa, 31982, Saudi Arabia
| | - Bader Alsubaie
- Agricultural Biotechnology Department, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa, 31982, Saudi Arabia
| | - Ahmed R Henawy
- Microbiology Department, Faculty of Agriculture, Cairo University, Giza, 12613, Egypt
| | - Adel A Rezk
- Agricultural Biotechnology Department, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa, 31982, Saudi Arabia
- Plant Virology Department, Plant Pathology Research Institute, Agriculture Research Center, Giza, 12619, Egypt
| | - Hayfa Habes Almutairi
- Chemistry Department, College of Science, King Faisal University, Al-Ahsa, 31982, Saudi Arabia
| | - Amal A Mohamed
- Chemistry Dept, Al-Leith University College, Umm Al-Qura University, P.O. Box 6725- 21955, Makkah, Saudi Arabia
| | - Nagwa I Elarabi
- Genetics Department, Faculty of Agriculture, Cairo University, Giza, 12613, Egypt
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Zhang Y, Zhou Q, Gao C, Lu Y, Sheng Y, Xiao M, Yun Y, Selvaraj JN, Zhang X, Li Y, Yu X. Endophytic bacteria for Cd remediation in rice: Unraveling the Cd tolerance mechanisms of Cupriavidus metallidurans CML2. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133846. [PMID: 38412644 DOI: 10.1016/j.jhazmat.2024.133846] [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: 11/29/2023] [Revised: 01/30/2024] [Accepted: 02/18/2024] [Indexed: 02/29/2024]
Abstract
The utility of endophytic bacteria in Cadmium (Cd) remediation has gained significant attention due to their ability to alleviate metal-induced stress and enhance plant growth. Here, we investigate C. metallidurans CML2, an endophytic bacterial strain prevalent in rice, showing resilience against 2400 mg/L of Cd(II). We conducted an in-depth integrated morphological and transcriptomic analysis illustrating the multifarious mechanisms CML2 employs to combat Cd, including the formation of biofilm and CdO nanoparticles, upregulation of genes involved in periplasmic immobilization, and the utilization of RND efflux pumps to extract excess Cd ions. Beyond Cd, CML2 exhibited robust tolerance to an array of heavy metals, including Mn2+, Se4+, Ni2+, Cu2+, and Hg2+, demonstrating effective Cd(II) removal capacity. Furthermore, CML2 has exhibited plant growth-promoting properties through the production of indole-3-acetic acid (IAA) at 0.93 mg/L, soluble phosphorus compounds at 1.11 mg/L, and siderophores at 22.67%. Supportively, pot experiments indicated an increase in root lengths and a decrease in Cd bioaccumulation in rice seedlings inoculated with CML2, consequently reducing Cd translocation rates from 43% to 31%. These findings not only contribute to the understanding of Cd resistance mechanisms in C. metallidurans, but also underscore CML2's promising application in Cd remediation within rice farming ecosystems.
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Affiliation(s)
- Yuan Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Qi Zhou
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Chang Gao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yue Lu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yang Sheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Ming Xiao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yueli Yun
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Jonathan Nimal Selvaraj
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Xianhua Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yadong Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Xuejing Yu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China.
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Alkhanjaf AAM, Sharma S, Sharma M, Kumar R, Arora NK, Kumar B, Umar A, Baskoutas S, Mukherjee TK. Microbial strategies for copper pollution remediation: Mechanistic insights and recent advances. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 346:123588. [PMID: 38401635 DOI: 10.1016/j.envpol.2024.123588] [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: 09/11/2023] [Revised: 02/06/2024] [Accepted: 02/14/2024] [Indexed: 02/26/2024]
Abstract
Environmental contamination is aninsistent concern affecting human health and the ecosystem. Wastewater, containing heavy metals from industrial activities, significantly contributes to escalating water pollution. These metals can bioaccumulate in food chains, posing health risks even at low concentrations. Copper (Cu), an essential micronutrient, becomes toxic at high levels. Activities like mining and fungicide use have led to Copper contamination in soil, water, and sediment beyond safe levels. Copper widely used in industries, demands restraint of heavy metal ion release into wastewater for ecosystem ultrafiltration, membrane filtration, nanofiltration, and reverse osmosis, combat heavy metal pollution, with emphasis on copper.Physical and chemical approaches are efficient, large-scale feasibility may have drawbackssuch as they are costly, result in the production of sludge. In contrast, bioremediation, microbial intervention offers eco-friendly solutions for copper-contaminated soil. Bacteria and fungi facilitate these bioremediation avenues as cost-effective alternatives. This review article emphasizes on physical, chemical, and biological methods for removal of copper from the wastewater as well asdetailing microorganism's mechanisms to mobilize or immobilize copper in wastewater and soil.
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Affiliation(s)
- Abdulrab Ahmed M Alkhanjaf
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Najran University, Najran, 11001, Saudi Arabia
| | - Sonu Sharma
- Department of Bio-sciences and Technology, Maharishi Markandeshwar (Deemed to Be University), Mullana, Ambala, 133207, Haryana, India
| | - Monu Sharma
- Department of Bio-sciences and Technology, Maharishi Markandeshwar (Deemed to Be University), Mullana, Ambala, 133207, Haryana, India
| | - Raman Kumar
- Department of Bio-sciences and Technology, Maharishi Markandeshwar (Deemed to Be University), Mullana, Ambala, 133207, Haryana, India.
| | - Naresh Kumar Arora
- Division of Soil and Crop Management, Central Soil Salinity Research Institute, Karnal, 133001, Haryana, India
| | - Brajesh Kumar
- Division of Soil and Crop Management, Central Soil Salinity Research Institute, Karnal, 133001, Haryana, India
| | - Ahmad Umar
- Department of Chemistry, Faculty of Science and Arts, Najran University, Najran, 11001, Saudi Arabia; Department of Materials Science and Engineering, The Ohio State University, Columbus, 43210, OH, USA
| | - Sotirios Baskoutas
- Department of Materials Science, University of Patras, 26500, Patras, Greece
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El-Beltagi HS, Halema AA, Almutairi ZM, Almutairi HH, Elarabi NI, Abdelhadi AA, Henawy AR, Abdelhaleem HAR. Draft genome analysis for Enterobacter kobei, a promising lead bioremediation bacterium. Front Bioeng Biotechnol 2024; 11:1335854. [PMID: 38260751 PMCID: PMC10800491 DOI: 10.3389/fbioe.2023.1335854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/18/2023] [Indexed: 01/24/2024] Open
Abstract
Lead pollution of the environment poses a major global threat to the ecosystem. Bacterial bioremediation offers a promising alternative to traditional methods for removing these pollutants, that are often hindered by various limitations. Our research focused on isolating lead-resistant bacteria from industrial wastewater generated by heavily lead-containing industries. Eight lead-resistant strains were successfully isolated, and subsequently identified through molecular analysis. Among these, Enterobacter kobei FACU6 emerged as a particularly promising candidate, demonstrating an efficient lead removal rate of 83.4% and a remarkable lead absorption capacity of 571.9 mg/g dry weight. Furthermore, E. kobei FACU6 displayed a remarkable a maximum tolerance concentration (MTC) for lead reaching 3,000 mg/L. To further investigate the morphological changes in E. kobei FACU6 in response to lead exposure, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed. These analyses revealed significant lead adsorption and intracellular accumulation in treated bacteria in contrast to the control bacterium. Whole-genome sequencing was performed to gain deeper insights into E. kobei's lead resistance mechanisms. Structural annotation revealed a genome size of 4,856,454 bp, with a G + C content of 55.06%. The genome encodes 4,655 coding sequences (CDS), 75 tRNA genes, and 4 rRNA genes. Notably, genes associated with heavy metal resistance and their corresponding regulatory elements were identified within the genome. Furthermore, the expression levels of four specific heavy metal resistance genes were evaluated. Our findings revealed a statistically significant upregulation in gene expression under specific environmental conditions, including pH 7, temperature of 30°C, and high concentrations of heavy metals. The outstanding potential of E. kobei FACU6 as a source of diverse genes related to heavy metal resistance and plant growth promotion makes it a valuable candidate for developing safe and effective strategies for heavy metal disposal.
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Affiliation(s)
- Hossam S. El-Beltagi
- Agricultural Biotechnology Department, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa, Saudi Arabi
- Biochemistry Department, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Asmaa A. Halema
- Genetics Department, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Zainab M. Almutairi
- Biology Department, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Hayfa Habes Almutairi
- Department of Chemistry, College of Science, King Faisal University, Al-Ahsa, Saudi Arabia
| | - Nagwa I. Elarabi
- Genetics Department, Faculty of Agriculture, Cairo University, Giza, Egypt
| | | | - Ahmed R. Henawy
- Microbiology Department, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Heba A. R. Abdelhaleem
- College of Biotechnology, Misr University for Science and Technology (MUST), 6th October City, Egypt
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12
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Mannacharaju M, Ganesan S, Lee JK, Rajagopal R, Chang SW, Ravindran B. Bacterial cell immobilized packed bed reactor for the elimination of dissolved organics from biologically treated post-tanning wastewater and its microbial community profile. CHEMOSPHERE 2023; 320:138022. [PMID: 36739983 DOI: 10.1016/j.chemosphere.2023.138022] [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: 10/15/2022] [Revised: 01/20/2023] [Accepted: 01/29/2023] [Indexed: 06/18/2023]
Abstract
In conventional, the biologically treated tannery wastewaters are rich in dissolved organics and the application of reverse osmosis (RO) to biologically treated tannery wastewater was challenged with fouling and failure of RO membrane due to existence of lingering dissolved organic compounds. In present investigation the bacterial cell immobilized packed bed reactor (CIPBR) was operated to remove the dissolved organic compounds in biologically treated post-tanning wastewater to avoid membrane fouling in RO. The efficient microbial syndicate to eliminate dissolved organics in post-tanning wastewater was isolated and immobilized on to the carbon silica matrix (CSM) in the range of 2.98 ± 0.2 × 107 cells gm-1 of CSM and the same was used as a carrier matrix in the packed bed reactor. The CIPBR established the CODtot, CODdis and BOD removal efficiency by 61 ± 4%, 57 ± 4% and 87 ± 3% respectively with CODtot, CODdis and BOD remained in the treated wastewater as 236 ± 21 mg/L, 228 ± 21 mg/L, and 12 ± 3 mg/L under continuous operation. The removal of dissolved organic compounds from the post-tanning wastewater was confirmed using UV-Visible and FT-IR spectroscopic studies. Among the total microbial community, the phylum Proteobacteria played most abundant role with 48.47% of relative abundance for the removal of dissolved organics in biologically treated post-tanning wastewater. The significance of the study is to replace the tertiary treatment unit operation in the conventional ETP/CETP to remove dissolved organics in wastewater.
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Affiliation(s)
- Mahesh Mannacharaju
- Environmental Science and Engineering Division, CSIR - Central Leather Research Institute (CLRI), Adyar, Chennai, 20, TN, India; Department of Chemical Engineering, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul, 05029, Republic of Korea
| | - Sekaran Ganesan
- Environmental Science and Engineering Division, CSIR - Central Leather Research Institute (CLRI), Adyar, Chennai, 20, TN, India; SRM Institute of Science and Technology, Ramapuram Campus, Chennai-600089, India.
| | - Jung-Kul Lee
- Department of Chemical Engineering, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul, 05029, Republic of Korea
| | - Rajinikanth Rajagopal
- Sherbrooke Research and Development Center, Agriculture and Agri-Food Canada, 2000 College Street, Sherbrooke, QC, J1M 0C8, Canada
| | - Soon Woong Chang
- Department of Environmental Energy and Engineering, Kyonggi University, Yeongtong-Gu, Suwon, Gyeonggi-Do, 16227, Republic of Korea
| | - Balasubramani Ravindran
- Department of Environmental Energy and Engineering, Kyonggi University, Yeongtong-Gu, Suwon, Gyeonggi-Do, 16227, Republic of Korea; Department of Medical Biotechnology and Integrative Physiology, Institute of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Thandalam, Chennai 602105, Tamil Nadu, India.
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Interplay between Two-Component Regulatory Systems Is Involved in Control of Cupriavidus metallidurans Metal Resistance Genes. J Bacteriol 2023; 205:e0034322. [PMID: 36892288 PMCID: PMC10127602 DOI: 10.1128/jb.00343-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023] Open
Abstract
Metal resistance of Cupriavidus metallidurans is based on determinants that were acquired in the past by horizontal gene transfer during evolution. Some of these determinants encode transmembrane metal efflux systems. Expression of most of the respective genes is controlled by two-component regulatory systems composed of a membrane-bound sensor/sensory histidine kinase (HK) and a cytoplasmic, DNA-binding response regulator (RR). Here, we investigated the interplay between the three closely related two-component regulatory systems CzcRS, CzcR2S2, and AgrRS. All three systems regulate the response regulator CzcR, while the RRs AgrR and CzcR2 were not involved in czc regulation. Target promoters were czcNp and czcPp for genes upstream and downstream of the central czc gene region. The two systems together repressed CzcRS-dependent upregulation of czcP-lacZ at low zinc concentrations in the presence of CzcS but activated this signal transmission at higher zinc concentrations. AgrRS and CzcR2S2 interacted to quench CzcRS-mediated expression of czcNp-lacZ and czcPp-lacZ. Together, cross talk between the three two-component regulatory systems enhanced the capabilities of the Czc systems by controlling expression of the additional genes czcN and czcP. IMPORTANCE Bacteria are able to acquire genes encoding resistance to metals and antibiotics by horizontal gene transfer. To bestow an evolutionary advantage on their host cell, new genes must be expressed, and their expression should be regulated so that resistance-mediating proteins are produced only when needed. Newly acquired regulators may interfere with those already present in a host cell. Such an event was studied here in the metal-resistant bacterium Cupriavidus metallidurans. The results demonstrate how regulation by the acquired genes interacts with the host's extant regulatory network. This leads to emergence of a new system level of complexity that optimizes the response of the cell to periplasmic signals.
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Structural Analyses of the Multicopper Site of CopG Support a Role as a Redox Enzyme. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1414:97-121. [PMID: 36637718 DOI: 10.1007/5584_2022_753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Metal ions can be both essential components of cells as well as potential toxins if present in excess. Organisms utilize a variety of protein systems to maintain the concentration of metal ions within the appropriate range for cellular function, and to avoid concentrations where cellular damage can occur. In bacteria, numerous proteins contribute to copper homeostasis, including copper transporters, chelators, and redox enzymes. The genes that encode these proteins are often found in clusters, thus providing modular components that work together to achieve homeostasis. A better understanding of how these components function and cooperate to achieve metal ion resistance is needed, given the extensive use of metal ions, including copper, as broad-spectrum biocides in a variety of clinical and environmental settings. The copG gene is a common component of such copper resistance clusters, but its contribution to copper resistance is not well understood. In this review the available information about the CopG protein encoded by this gene is summarized. Comparison of the recent structure to diverse copper-containing metallochaperones, metalloenzymes, and electron transfer proteins suggests that CopG is a redox enzyme that uses multiple copper ions as active site redox cofactors to act on additional copper ion substrates. Mechanisms for both oxidase and reductase activity are proposed, and the biological advantages that these activities can contribute in conjunction with existing systems are described.
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Naykodi A, Patankar SC, Thorat BN. Alkaliphiles for comprehensive utilization of red mud (bauxite residue)-an alkaline waste from the alumina refinery. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:9350-9368. [PMID: 36480139 DOI: 10.1007/s11356-022-24190-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 11/09/2022] [Indexed: 06/17/2023]
Abstract
The mining industry has powered the human endeavor to make life more innovative, flexible, and comfortable. However, it has also led to concerns due to the increasing amount of mining and associated industrial waste. Special attention is highly desired for its proper management and safe disposal in the environment. The problem has only augmented with the increase in the mining costs because of the investments needed for ecological remediation after the mining operation. It is pertinent that the targeted technologies need to be developed to utilize mining and associated industrial waste as a secondary resource to ensure sustainable mining operations. Every perceived waste is a valuable resource that is needed to be utilized to create additional value. In this review, the case of alkaline bauxite residue (red mud)-alumina refinery waste has been discussed at length. The highlight of the proposed work is to understand the importance of alkaliphile-assisted biomining-a sustainable alternative to conventional metal recovery processes. Along with the recovery of metals, pH reduction of red mud is possible through biomining, which ultimately paves the way for its complete utilization. The unique adaptation strategies of alkaliphiles make them more suitable for biomining of red mud through bioleaching, biosorption, and bioaccumulation, which have been discussed here. Furthermore, we have focused on the potential of the indigenous microflora of red mud for metal recovery in addition to its neutralization. The study of indigenous alkaliphiles from red mud, including its isolation and propagation, is crucial for the industrial-scale application of alkaliphile-based technology and has been emphasized.
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Affiliation(s)
- Ankita Naykodi
- Department of Biotechnology, Institute of Chemical Technology-IndianOil Odisha Campus, Bhubaneswar, 751013, Odisha, India
| | - Saurabh C Patankar
- Department of Chemical Engineering, Institute of Chemical Technology-IndianOil Odisha Campus, Bhubaneswar, 751013, Odisha, India
| | - Bhaskar N Thorat
- Department of Chemical Engineering, Institute of Chemical Technology, Mumbai, 400019, India.
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16
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Ducret V, Gonzalez D, Perron K. Zinc homeostasis in Pseudomonas. Biometals 2022:10.1007/s10534-022-00475-5. [PMID: 36472780 PMCID: PMC10393844 DOI: 10.1007/s10534-022-00475-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022]
Abstract
AbstractIn the genus Pseudomonas, zinc homeostasis is mediated by a complete set of import and export systems, whose expression is precisely controlled by three transcriptional regulators: Zur, CzcR and CadR. In this review, we describe in detail our current knowledge of these systems, their regulation, and the biological significance of zinc homeostasis, taking Pseudomonas aeruginosa as our paradigm. Moreover, significant parts of this overview are dedicated to highlight interactions and cross-regulations between zinc and copper import/export systems, and to shed light, through a review of the literature and comparative genomics, on differences in gene complement and function across the whole Pseudomonas genus. The impact and importance of zinc homeostasis in Pseudomonas and beyond will be discussed throughout this review.
Graphical abstract
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17
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Li N, Li H, Zhu C, Liu C, Su G, Chen J. Controlling AMR in the Pig Industry: Is It Enough to Restrict Heavy Metals? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:11265. [PMID: 36141538 PMCID: PMC9517514 DOI: 10.3390/ijerph191811265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 06/16/2023]
Abstract
Heavy metals have the potential to influence the transmission of antimicrobial resistance (AMR). However, the effect on AMR caused by heavy metals has not been clearly revealed. In this study, we used a microcosm experiment and metagenomics to examine whether common levels of Cu and Zn in pig manure influence AMR transmission in manured soil. We found that the abundance of 204 ARGs significantly increased after manure application, even though the manure did not contain antibiotic residuals. However, the combined addition of low Cu and Zn (500 and 1000 mg/kg, respectively) only caused 14 ARGs to significantly increase, and high Cu and Zn (1000 and 3000 mg/kg, respectively) caused 27 ARGs to significantly increase. The disparity of these numbers suggested that factors within the manure were the primary driving reasons for AMR transmission, rather than metal amendments. A similar trend was found for biocide and metal resistance genes (BMRGs) and mobile genetic elements (MGEs). This study offers deeper insights into AMR transmission in relation to the effects of manure application and heavy metals at commonly reported levels. Our findings recommend that more comprehensive measures in controlling AMR in the pig industry are needed apart from restricting heavy metal additions.
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Affiliation(s)
- Na Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Institute for Public Safety Research, Tsinghua University, Beijing 100084, China
| | - Hongna Li
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Changxiong Zhu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Chong Liu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Guofeng Su
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Institute for Public Safety Research, Tsinghua University, Beijing 100084, China
| | - Jianguo Chen
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Institute for Public Safety Research, Tsinghua University, Beijing 100084, China
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18
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Wang X, Wu H, Dai C, Wang X, Wang L, Xu J, Lu Z. Microbial interactions enhanced environmental fitness and expanded ecological niches under dibutyl phthalate and cadmium co-contamination. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 306:119362. [PMID: 35489538 DOI: 10.1016/j.envpol.2022.119362] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/14/2022] [Accepted: 04/23/2022] [Indexed: 06/14/2023]
Abstract
Co-contamination of organic pollutants and heavy metals is universal in the natural environment. Dibutyl phthalate (DBP), a typical plasticizer, frequently coexists with cadmium (Cd) in nature. However, little attention has been given to the impacts of co-contamination by DBP and Cd on microbial communities or the responses of microbes. To address this, a microcosm experiment was conducted by supplying the exogenous DBP-degrading bacterium Glutamicibacter nicotianae ZM05 to investigate the interplay among DBP-Cd co-contamination, the exogenous DBP-degrading bacterium G. nicotianae ZM05, and indigenous microorganisms. To adapt to co-contamination stress, microbial communities adjust their diversity, interactions, and functions. The stability of the microbial community decreased under co-contamination, as evidenced by lower diversity, simpler network, and fewer ecological niches. Microbial interactions were strengthened, as evidenced by enriched pathways related to microbial communications. Meanwhile, interactions between microorganisms enhanced the environmental fitness of the exogenous DBP-degrading bacterium ZM05. Based on co-occurrence network prediction and coculture experiments, metabolic interactions between the non-DBP-degrading bacterium Cupriavidus metallidurans ZM16 and ZM05 were proven. Strain ZM16 utilized protocatechuic acid, a DBP downstream metabolite, to relieve acid inhibition and adsorbed Cd to relieve toxic stress. These findings help to explain the responses of bacterial and fungal communities to DBP-Cd co-contamination and provide new insights for the construction of degrading consortia for bioremediation.
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Affiliation(s)
- Xuejun Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Hao Wu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Chuhan Dai
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Xiaoyu Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Lvjing Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jianming Xu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Zhenmei Lu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China.
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Sun S, Zhang K, Wu Y, Zhu N, Wang Y, Chen J, Leng F. Transporter drives the biosorption of heavy metals by Stenotrophomonas rhizophila JC1. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:45380-45395. [PMID: 35143001 DOI: 10.1007/s11356-022-18900-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
To better understand the function of transporter in heavy metal detoxification of bacteria, the transporters associated with heavy metal detoxification in S. rhizophila JC1 were analyzed, among which four members were verified by RT-qPCR. In addition, the removal rates of four single metal ions (Cr6+, Cu2+, Zn2+, Pb2+) and polymetallic ions by strain JC1 were studied, respectively. We also researched the physiological response of strain JC1 to different metal stress via morphological observation, elemental composition, functional group and membrane permeability analysis. The results showed that in the single metal ion solution, removal capacities of Cu2+ (120 mg/L) and Cr6+ (80 mg/L) of S. rhizophila JC1 reached to 79.9% and 89.3%, respectively, while in polymetallic ions solution, the removal capacity of each metal ion all decreased, and in detail, the adsorption capacity was determined Cr6+>Cu2+>Zn2+>Pb2+ under the same condition. The physiological response analyses results showed that extracellular adsorption phenomena occurred, and the change of membrane permeability hindered the uptake of metal ions by bacteria. The analysis of transporters in strain JC1 genome illustrated that a total of 323 transporters were predicted. Among them, two, six and five proteins of the cation diffusion facilitator, resistance-nodulation-division efflux and P-type ATPase families were, respectively, predicted. The expression of corresponding genes showed that the synergistic action of correlative transporters played important roles in the process of adsorption. The comparative genomics analysis revealed that S. rhizophila JC1 has long-distance evolutionary relationships with other strains, but the efflux system of S. rhizophila JC1 contained the same types of metal transporters as other metal-resistant bacteria.
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Affiliation(s)
- Shangchen Sun
- School of Petrochemical Engineering, Lanzhou University of Technology, 730050, Lanzhou, China
| | - Kexin Zhang
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China
| | - Yamiao Wu
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China
| | - Ning Zhu
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China
| | - Yonggang Wang
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China.
| | - Jixiang Chen
- School of Petrochemical Engineering, Lanzhou University of Technology, 730050, Lanzhou, China
| | - Feifan Leng
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China
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Importance of RpoD- and Non-RpoD-Dependent Expression of Horizontally Acquired Genes in Cupriavidus metallidurans. Microbiol Spectr 2022; 10:e0012122. [PMID: 35311568 PMCID: PMC9045368 DOI: 10.1128/spectrum.00121-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome of the metal-resistant, hydrogen-oxidizing bacterium Cupriavidus metallidurans contains a large number of horizontally acquired plasmids and genomic islands that were integrated into its chromosome or chromid. For the C. metallidurans CH34 wild-type strain growing under nonchallenging conditions, 5,763 transcriptional starting sequences (TSSs) were determined. Using a custom-built motif discovery software based on hidden Markov models, patterns upstream of the TSSs were identified. The pattern TTGACA, −35.6 ± 1.6 bp upstream of the TSSs, in combination with a TATAAT sequence 15.8 ± 1.4 bp upstream occurred frequently, especially upstream of the TSSs for 48 housekeeping genes, and these were assigned to promoters used by RNA polymerase containing the main housekeeping sigma factor RpoD. From patterns upstream of the housekeeping genes, a score for RpoD-dependent promoters in C. metallidurans was derived and applied to all 5,763 TSSs. Among these, 2,572 TSSs could be associated with RpoD with high probability, 373 with low probability, and 2,818 with no probability. In a detailed analysis of horizontally acquired genes involved in metal resistance and not involved in this process, the TSSs responsible for the expression of these genes under nonchallenging conditions were assigned to RpoD- or non-RpoD-dependent promoters. RpoD-dependent promoters occurred frequently in horizontally acquired metal resistance and other determinants, which should allow their initial expression in a new host. However, other sigma factors and sense/antisense effects also contribute—maybe to mold in subsequent adaptation steps the assimilated gene into the regulatory network of the cell. IMPORTANCE In their natural environment, bacteria are constantly acquiring genes by horizontal gene transfer. To be of any benefit, these genes should be expressed. We show here that the main housekeeping sigma factor RpoD plays an important role in the expression of horizontally acquired genes in the metal-resistant hydrogen-oxidizing bacterium C. metallidurans. By conservation of the RpoD recognition consensus sequence, a newly arriving gene has a high probability to be expressed in the new host cell. In addition to integrons and genes travelling together with that for their sigma factor, conservation of the RpoD consensus sequence may be an important contributor to the overall evolutionary success of horizontal gene transfer in bacteria. Using C. metallidurans as an example, this publication sheds some light on the fate and function of horizontally acquired genes in bacteria.
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Alviz-Gazitua P, Durán RE, Millacura FA, Cárdenas F, Rojas LA, Seeger M. Cupriavidus metallidurans CH34 Possesses Aromatic Catabolic Versatility and Degrades Benzene in the Presence of Mercury and Cadmium. Microorganisms 2022; 10:microorganisms10020484. [PMID: 35208938 PMCID: PMC8879955 DOI: 10.3390/microorganisms10020484] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/17/2022] [Accepted: 02/17/2022] [Indexed: 11/16/2022] Open
Abstract
Heavy metal co-contamination in crude oil-polluted environments may inhibit microbial bioremediation of hydrocarbons. The model heavy metal-resistant bacterium Cupriavidus metallidurans CH34 possesses cadmium and mercury resistance, as well as genes related to the catabolism of hazardous BTEX aromatic hydrocarbons. The aims of this study were to analyze the aromatic catabolic potential of C. metallidurans CH34 and to determine the functionality of the predicted benzene catabolic pathway and the influence of cadmium and mercury on benzene degradation. Three chromosome-encoded bacterial multicomponent monooxygenases (BMMs) are involved in benzene catabolic pathways. Growth assessment, intermediates identification, and gene expression analysis indicate the functionality of the benzene catabolic pathway. Strain CH34 degraded benzene via phenol and 2-hydroxymuconic semialdehyde. Transcriptional analyses revealed a transition from the expression of catechol 2,3-dioxygenase (tomB) in the early exponential phase to catechol 1,2-dioxygenase (catA1 and catA2) in the late exponential phase. The minimum inhibitory concentration to Hg (II) and Cd (II) was significantly lower in the presence of benzene, demonstrating the effect of co-contamination on bacterial growth. Notably, this study showed that C. metallidurans CH34 degraded benzene in the presence of Hg (II) or Cd (II).
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Affiliation(s)
- Pablo Alviz-Gazitua
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
- Departamento de Ciencias Biológicas y Biodiversidad, Universidad de los Lagos, Osorno 5311890, Chile
| | - Roberto E. Durán
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
| | - Felipe A. Millacura
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JQ, UK
| | - Franco Cárdenas
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
- Centro Regional de Estudios en Alimentos Saludables (CREAS), Avenida Universidad 330, Curauma, Valparaíso 2373223, Chile
| | - Luis A. Rojas
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, Avenida Angamos 610, Antofagasta 1270709, Chile;
| | - Michael Seeger
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
- Correspondence: or
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Butler J, Kelly SD, Muddiman KJ, Besinis A, Upton M. Hospital sink traps as a potential source of the emerging multidrug-resistant pathogen Cupriavidus pauculus: characterization and draft genome sequence of strain MF1. J Med Microbiol 2022; 71. [PMID: 35113779 PMCID: PMC8941954 DOI: 10.1099/jmm.0.001501] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Introduction.Cupriavidus pauculus is historically found in soil and water but has more recently been reported to cause human infection and death. Hospital sink traps can serve as a niche for bacterial persistence and a platform for horizontal gene transfer, with evidence of dissemination of pathogens in hospital plumbing systems driving nosocomial infection. Gap Statement. This paper presents the first C. pauculus strain isolated from a hospital sink trap. There are only six genome assemblies available on NCBI for C. pauculus; two of these are PacBio/Illumina hybrids. This paper presents the first ONT/Illumina hybrid assembly, with five contigs. The other assemblies available consist of 37, 38, 111 and 227 contigs. This paper also presents data on biofilm formation and lethal dose in Galleria mellonella; there is little published information describing these aspects of virulence. Aim. The aims were to identify the isolate found in a hospital sink trap, characterize its genome, and assess whether it could pose a risk to human health. Methodology. The genome was sequenced, and a hybrid assembly of short and long reads produced. Antimicrobial susceptibility was determined by the broth microdilution method. Virulence was assessed by measuring in vitro biofilm formation compared to Pseudomonas aeruginosa and in vivo lethality in Galleria mellonella larvae. Results. The isolate was confirmed to be a strain of C. pauculus, with a 6.8 Mb genome consisting of 6468 coding sequences and an overall G+C content of 63.9 mol%. The genome was found to contain 12 antibiotic resistance genes, 8 virulence factor genes and 33 metal resistance genes. The isolate can be categorized as resistant to meropenem, amoxicillin, amikacin, gentamicin and colistin, but susceptible to cefotaxime, cefepime, imipenem and ciprofloxacin. Clear biofilm formation was seen in all conditions over 72 h and exceeded that of P. aeruginosa when measured at 37 °C in R2A broth. Lethality in G. mellonella larvae over 48 h was relatively low. Conclusion. The appearance of a multidrug-resistant strain of C. pauculus in a known pathogen reservoir within a clinical setting should be considered concerning. Further work should be completed to compare biofilm formation and in vivo virulence between clinical and environmental strains, to determine how easily environmental strains may establish human infection. Infection control teams and clinicians should be aware of the emerging nature of this pathogen and further work is needed to minimize the impact of contaminated hospital plumbing systems on patient outcomes.
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Affiliation(s)
- James Butler
- School of Engineering, Computing and Mathematics, Faculty of Science and Engineering, University of Plymouth, Plymouth PL4 8AA, UK
| | - Sean D Kelly
- School of Biomedical Sciences, Faculty of Health, University of Plymouth, Plymouth PL4 8AA, UK
| | - Katie J Muddiman
- School of Biomedical Sciences, Faculty of Health, University of Plymouth, Plymouth PL4 8AA, UK
| | - Alexandros Besinis
- School of Engineering, Computing and Mathematics, Faculty of Science and Engineering, University of Plymouth, Plymouth PL4 8AA, UK.,Peninsula Dental School, Faculty of Health, University of Plymouth, Plymouth PL4 8AA, UK
| | - Mathew Upton
- School of Biomedical Sciences, Faculty of Health, University of Plymouth, Plymouth PL4 8AA, UK
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Loss of mobile genomic islands in metal resistant, hydrogen-oxidizing Cupriavidus metallidurans. Appl Environ Microbiol 2021; 88:e0204821. [PMID: 34910578 DOI: 10.1128/aem.02048-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome of the metal resistant, hydrogen-oxidizing bacterium Cupriavidus metallidurans strain CH34 contains horizontally acquired plasmids and genomic islands. Metal-resistance determinants on the two plasmids may exert genetic dominance over other related determinants. To investigate whether these recessive determinants can be activated in the absence of the dominant ones, the transcriptome of the highly zinc-sensitive deletion mutant Δe4 (ΔcadA ΔzntA ΔdmeF ΔfieF) of the plasmid-free parent AE104 was characterized using gene arrays. As a consequence of some unexpected results, close examination by PCR and genomic re-resequencing of strains CH34, AE104, Δe4 and others revealed that the genomic islands CMGIs 2, 3, 4, D, E, but no other islands or recessive determinants, were deleted in some of these strains. Provided CH34 wild type was kept under alternating zinc and nickel selection pressure, no comparable deletions occurred. All current data suggest that genes were actually deleted and were not, as previously surmised, simply absent from the respective strain. As a consequence, a cured database was compiled from the newly generated and previously published gene array data. Analysis of data from this database indicated that some genes of recessive, no longer needed determinants were nevertheless expressed and up-regulated. Their products may interact with those of the dominant determinants to mediate a mosaic phenotype. The ability to contribute to such a mosaic phenotype may prevent deletion of the recessive determinant. The data suggest that the bacterium actively modifies its genome to deal with metal stress and the same time ensures metal homeostasis. Significance In their natural environment, bacteria continually acquire genes by horizontal gene transfer and newly acquired determinants may become dominant over related ones already present in the host genome. When a bacterium is taken into laboratory culture, it is isolated from the horizontal gene transfer network. It can no longer gain genes, but instead may lose them. This was indeed observed in Cupriavidus metallidurans for loss key metal-resistance determinants when no selection pressure was continuously kept. However, some recessive metal-resistance determinants were maintained in the genome. It is proposed that they might contribute some accessory genes to related dominant resistance determinants, for instance periplasmic metal-binding proteins or two-component regulatory systems. Alternatively, they may only remain in the genome because their DNA serves as a scaffold for the nucleoid. Using C. metallidurans as an example, this study sheds light on the fate and function of horizontally acquired genes in bacteria.
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Peng J, Ma J, Wei X, Zhang C, Jia N, Wang X, Wang ET, Hu D, Wang Z. Accumulation of beneficial bacteria in the rhizosphere of maize (Zea mays L.) grown in a saline soil in responding to a consortium of plant growth promoting rhizobacteria. ANN MICROBIOL 2021. [DOI: 10.1186/s13213-021-01650-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Abstract
Purpose
Salt stress reduces plant growth and is now becoming one of the most important factors restricting the agricultural productivity. Inoculation of plant growth-promoting rhizobacteria (PGPR) has been shown to confer plant tolerance against abiotic stress, but the detailed mechanisms of how this occurs remain unclear and the application effects in different reports are unstable. In order to obtain a favorite effect of PGPR inoculation and improve our knowledge about the related mechanism, we performed this study to analyze the mechanism of a PGPR consortium on improving the salt resistance of crops.
Methods
A region-specific (Saline land around Bohai Sea in China) PGPR consortium was selected that contains three strains (Pseudomonas sp. P8, Peribacillus sp. P10, and Streptomyces sp. X52) isolated from rhizosphere of Sonchus brachyotus DC. grown in a saline soil. By inoculation tests, their plant growth-promoting (PGP) traits and ability to improve the salt resistance of maize were investigated and shifting in rhizosphere bacterial community of the inoculated plants was analyzed using the high-throughput sequencing technology.
Results
The three selected strains were salt tolerant, presented several growth promoting properties, and inhibited several phytopathogenic fungi. The inoculation of this consortium promoted the growth of maize plant and enriched the beneficial bacteria in rhizosphere of maize in a saline soil, including the nitrogen fixing bacteria Azotobacter, Sinorhizobium, and Devosia, and the nitrification bacteria Candidatus Nitrososphaera, and Nitrosovibrio.
Conclusions
The bacterial consortium P8/P10/X52 could improve plant growth in a saline soil by both their PGP traits and regulating the rhizosphere bacterial community. The findings provided novel information about how the PGPR helped the plants in the view of microbiome.
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Behind the shield of Czc: ZntR controls expression of the gene for the zinc-exporting P-type ATPase ZntA in Cupriavidus metallidurans. J Bacteriol 2021; 203:JB.00052-21. [PMID: 33685972 PMCID: PMC8117531 DOI: 10.1128/jb.00052-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the metallophilic beta-proteobacterium Cupriavidus metallidurans, the plasmid-encoded Czc metal homeostasis system adjusts the periplasmic zinc, cobalt and cadmium concentration, which influences subsequent uptake of these metals into the cytoplasm. Behind this shield, the PIB2-type APTase ZntA is responsible for removal of surplus cytoplasmic zinc ions, thereby providing a second level of defense against toxic zinc concentrations. ZntA is the counterpart to the Zur-regulated zinc uptake system ZupT and other import systems; however, the regulator of zntA expression was unknown. The chromid-encoded zntA gene is adjacent to the genes czcI2C2B2', which are located on the complementary DNA strand and transcribed from a common promoter region. These genes encode homologs of plasmid pMOL30-encoded Czc components. Candidates for possible regulators of zntA were identified and subsequently tested: CzcI, CzcI2, and the MerR-type gene products of the locus tags Rmet_2302, Rmet_0102, Rmet_3456. This led to the identification of Rmet_3456 as ZntR, the main regulator of zntA expression. Moreover, both CzcIs decreased Czc-mediated metal resistance, possibly to avoid "over-excretion" of periplasmic zinc ions, which could result in zinc starvation due to diminished zinc uptake into the cytoplasm. Rmet_2302 was identified as CadR, the regulator of the cadA gene for an important cadmium-exporting PIB2-type ATPase, which provides another system for removal of cytoplasmic zinc and cadmium. Rmet_0102 was not involved in regulation of the metal resistance systems examined here. Thus, ZntR forms a complex regulatory network with CadR, Zur and the CzcIs. Moreover, these discriminating regulatory proteins assign the efflux systems to their particular function.ImportanceZinc is an essential metal for numerous organisms from humans to bacteria. The transportome of zinc uptake and efflux systems controls the overall cellular composition and zinc content in a double feed-back loop. Zinc starvation mediates, via the Zur regulator, an up-regulation of the zinc import capacity via the ZIP-type zinc importer ZupT and an amplification of zinc storage capacity, which together raise the cellular zinc content again. On the other hand, an increasing zinc content leads to ZntR-mediated up-regulation of the zinc efflux system ZntA, which decreases the zinc content. Together, the Zur regulon components and ZntR/ZntA balance the cellular zinc content under both high external zinc concentrations and zinc starvation conditions.
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Butz ZJ, Hendricks A, Borgognoni K, Ackerson CJ. Identification of a TeO32- reductase/mycothione reductase from Rhodococcus erythropolis PR4. FEMS Microbiol Ecol 2021; 97:5974521. [PMID: 33377161 DOI: 10.1093/femsec/fiaa220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/09/2020] [Indexed: 01/30/2023] Open
Abstract
A Rhodococcus erythropolis bacterium that tolerates normally lethal concentrations of Fe(II), Cu(II), AsO32-, SeO32-, TeO32-, Cd(II) and Zn(II) was identified from an environmental isolate. In characterizing the molecular basis for metal tolerance, a mycothione reductase (Mtr) with remarkable selectivity for TeO32- reduction over SeO32- was identified. In equimolar concentrations of TeO32- and SeO32-, the enzymatic product contains a 7-fold excess of Te. This selectivity is remarkable because the standard reduction potential of SeO32- is 0.20 V more favorable for reduction than TeO32. Selectivity of the enzyme for TeO32- decreases with increasing assay pH. Homology modeling of the enzyme identifies four aromatic residues near the active site, including two histidine residues, that are not present in a related SeO32- preferring reductase. On the basis of more favorable π-interactions for Te than for Se and the pH dependence of the selectivity, the Te-selectivity is attributed in part to these aromatic residues. The resulting Te0 enzymatic product resembles Te nanowires.
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Affiliation(s)
- Zachary J Butz
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | | | - Kanda Borgognoni
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
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Giachino A, Focarelli F, Marles-Wright J, Waldron KJ. Synthetic biology approaches to copper remediation: bioleaching, accumulation and recycling. FEMS Microbiol Ecol 2021; 97:6021318. [PMID: 33501489 DOI: 10.1093/femsec/fiaa249] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/02/2020] [Indexed: 12/20/2022] Open
Abstract
One of the current aims of synthetic biology is the development of novel microorganisms that can mine economically important elements from the environment or remediate toxic waste compounds. Copper, in particular, is a high-priority target for bioremediation owing to its extensive use in the food, metal and electronic industries and its resulting common presence as an environmental pollutant. Even though microbe-aided copper biomining is a mature technology, its application to waste treatment and remediation of contaminated sites still requires further research and development. Crucially, any engineered copper-remediating chassis must survive in copper-rich environments and adapt to copper toxicity; they also require bespoke adaptations to specifically extract copper and safely accumulate it as a human-recoverable deposit to enable biorecycling. Here, we review current strategies in copper bioremediation, biomining and biorecycling, as well as strategies that extant bacteria use to enhance copper tolerance, accumulation and mineralization in the native environment. By describing the existing toolbox of copper homeostasis proteins from naturally occurring bacteria, we show how these modular systems can be exploited through synthetic biology to enhance the properties of engineered microbes for biotechnological copper recovery applications.
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Affiliation(s)
- Andrea Giachino
- Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Francesca Focarelli
- Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Jon Marles-Wright
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Kevin J Waldron
- Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
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Zhang K, Xin R, Zhao Z, Li W, Wang Y, Wang Q, Niu Z, Zhang Y. Mobile genetic elements are the Major driver of High antibiotic resistance genes abundance in the Upper reaches of huaihe River Basin. JOURNAL OF HAZARDOUS MATERIALS 2021; 401:123271. [PMID: 32629348 DOI: 10.1016/j.jhazmat.2020.123271] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 06/16/2020] [Accepted: 06/20/2020] [Indexed: 05/12/2023]
Abstract
Rivers are considered a vital reservoir of antibiotic resistance genes (ARGs) and are critical to disseminate ARGs. The present study delved into the ARGs pollution of the sediments in the upper reaches of Huaihe river, one of the seven longest rivers in China, by high-throughput quantitative PCR. Subsequently, the relationship between ARGs and the bacterial community/mobile genetic elements (MGEs) was determined. As revealed from the results, the overall ARGs ranged from 2.65×10-3 to 6.14×10-2/16S copies, and the abundance of ARGs in the tributaries was significantly higher than that in the mainstreams (p<0.05). Moreover, the ARGs introduced by tributaries were capable of affecting the whole mainstream of Huaihe river. As suggested from the results of co-occurrence analysis and pRDA analysis, MGEs were reported as the major driver to disseminate ARGs in the upper reaches of Huaihe river basin. The larger the MGEs proportion, the higher the likelihood of ARGs transferring from antibiotic resistance bacteria to human pathogens in Huaihe river.
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Affiliation(s)
- Kai Zhang
- School of Geographic Sciences, Xinyang Normal University, Xinyang, 464000, China; Henan Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution, Xinyang Normal University, Xinyang, 464000, China
| | - Rui Xin
- School of Marine Science and Technology, Tianjin University, Tianjin, 300072, China
| | - Ze Zhao
- School of Marine Science and Technology, Tianjin University, Tianjin, 300072, China
| | - Wenpeng Li
- School of Marine Science and Technology, Tianjin University, Tianjin, 300072, China
| | - Yanan Wang
- School of Geographic Sciences, Xinyang Normal University, Xinyang, 464000, China; Henan Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution, Xinyang Normal University, Xinyang, 464000, China
| | - Qian Wang
- School of Geographic Sciences, Xinyang Normal University, Xinyang, 464000, China; Henan Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution, Xinyang Normal University, Xinyang, 464000, China
| | - Zhiguang Niu
- School of Marine Science and Technology, Tianjin University, Tianjin, 300072, China
| | - Ying Zhang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China.
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29
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Minari GD, Saran LM, Lima Constancio MT, Correia da Silva R, Rosalen DL, José de Melo W, Carareto Alves LM. Bioremediation potential of new cadmium, chromium, and nickel-resistant bacteria isolated from tropical agricultural soil. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 204:111038. [PMID: 32739674 DOI: 10.1016/j.ecoenv.2020.111038] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/30/2020] [Accepted: 07/13/2020] [Indexed: 05/26/2023]
Abstract
Soil management using fertilizers can modify soil chemical, biochemical and biological properties, including the concentration of trace-elements as cadmium (Cd), chromium (Cd) and nickel (Ni). Bacterial isolates from Cd, Cr, and Ni-contaminated soil were evaluated for some characteristics for their use in bioremediation. Isolates (592) were obtained from soil samples (19) of three areas used in three maize cultivation systems: no-tillage and conventional tillage with the application of mineral fertilizers; minimum tillage with the application of sewage sludge. Four isolates were resistant to Cr3+ (3.06 mmol dm-3) and Cd2+ (2.92 mmol dm-3). One isolate was resistant to the three metals at 0.95 mmol dm-3. All isolates developed in a medium of Cd2+, Cr3+ and Ni2+ at 0.5 mmol dm-3, and removed Cd2+ (17-33%) and Cr6+ (60-70%). They were identified by sequencing of the gene 16S rRNA, as bacteria of the genera Paenibacillus, Burkholderia, Ensifer, and two Cupriavidus. One of the Cupriavidus isolate was able to remove 60% of Cr6+ from the culture medium and showed high indole acetic acid production capacity. We evaluated it in a microbe-plant system that could potentially be deployed in bioremediation by removing toxic metals from contaminated soil.
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Affiliation(s)
- Guilherme Deomedesse Minari
- São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Department of Technology, Jaboticabal, Brazil
| | - Luciana Maria Saran
- São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Department of Technology, Jaboticabal, Brazil.
| | - Milena Tavares Lima Constancio
- São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Department of Technology, Jaboticabal, Brazil
| | - Rafael Correia da Silva
- São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Department of Technology, Jaboticabal, Brazil
| | - David Luciano Rosalen
- São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Department of Rural Engineering, Jaboticabal, Brazil
| | - Wanderley José de Melo
- São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Department of Technology, Jaboticabal, Brazil; Brasil University, Descalvado, Brazil
| | - Lúcia Maria Carareto Alves
- São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Department of Technology, Jaboticabal, Brazil
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Steunou AS, Babot M, Bourbon M, Tambosi R, Durand A, Liotenberg S, Krieger‐Liszkay A, Yamaichi Y, Ouchane S. Additive effects of metal excess and superoxide, a highly toxic mixture in bacteria. Microb Biotechnol 2020; 13:1515-1529. [PMID: 32558268 PMCID: PMC7415354 DOI: 10.1111/1751-7915.13589] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 01/06/2023] Open
Abstract
Heavy metal contamination is a serious environmental problem. Understanding the toxicity mechanisms may allow to lower concentration of metals in the metal-based antimicrobial treatments of crops, and reduce metal content in soil and groundwater. Here, we investigate the interplay between metal efflux systems and the superoxide dismutase (SOD) in the purple bacterium Rubrivivax gelatinosus and other bacteria through analysis of the impact of metal accumulation. Exposure of the Cd2+ -efflux mutant ΔcadA to Cd2+ caused an increase in the amount and activity of the cytosolic Fe-Sod SodB, thereby suggesting a role of SodB in the protection against Cd2+ . In support of this conclusion, inactivation of sodB gene in the ΔcadA cells alleviated detoxification of superoxide and enhanced Cd2+ toxicity. Similar findings were described in the Cu+ -efflux mutant with Cu+ . Induction of the Mn-Sod or Fe-Sod in response to metals in other bacteria, including Escherichia coli, Pseudomonas aeruginosa, Pseudomonas putida, Vibrio cholera and Bacillus subtilis, was also shown. Both excess Cd2+ or Cu+ and superoxide can damage [4Fe-4S] clusters. The additive effect of metal and superoxide on the [4Fe-4S] could therefore explain the hypersensitive phenotype in mutants lacking SOD and the efflux ATPase. These findings underscore that ROS defence system becomes decisive for bacterial survival under metal excess.
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Affiliation(s)
- Anne Soisig Steunou
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
| | - Marion Babot
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
| | - Marie‐Line Bourbon
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
| | - Reem Tambosi
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
| | - Anne Durand
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
| | - Sylviane Liotenberg
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
| | - Anja Krieger‐Liszkay
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
| | - Yoshiharu Yamaichi
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
| | - Soufian Ouchane
- Institute for Integrative Biology of the Cell (I2BC)CEACNRSUniversité Paris‐Saclay91198Gif‐sur‐YvetteFrance
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Steunou AS, Durand A, Bourbon ML, Babot M, Tambosi R, Liotenberg S, Ouchane S. Cadmium and Copper Cross-Tolerance. Cu + Alleviates Cd 2 + Toxicity, and Both Cations Target Heme and Chlorophyll Biosynthesis Pathway in Rubrivivax gelatinosus. Front Microbiol 2020; 11:893. [PMID: 32582041 PMCID: PMC7283390 DOI: 10.3389/fmicb.2020.00893] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/16/2020] [Indexed: 11/17/2022] Open
Abstract
Cadmium, although not redox active is highly toxic. Yet, the underlying mechanisms driving toxicity are still to be characterized. In this study, we took advantage of the purple bacterium Rubrivivax gelatinosus strain with defective Cd2 +-efflux system to identify targets of this metal. Exposure of the ΔcadA strain to Cd2 + causes a decrease in the photosystem amount and in the activity of respiratory complexes. As in case of Cu+ toxicity, the data indicated that Cd2 + targets the porphyrin biosynthesis pathway at the level of HemN, a S-adenosylmethionine and CxxxCxxC coordinated [4Fe-4S] containing enzyme. Cd2 + exposure therefore results in a deficiency in heme and chlorophyll dependent proteins and metabolic pathways. Given the importance of porphyrin biosynthesis, HemN represents a key metal target to account for toxicity. In the environment, microorganisms are exposed to mixture of metals. Nevertheless, the biological effects of such mixtures, and the toxicity mechanisms remain poorly addressed. To highlight a potential cross-talk between Cd2 + and Cu+ -efflux systems, we show (i) that Cd2 + induces the expression of the Cd2 +-efflux pump CadA and the Cu+ detoxification system CopA and CopI; and (ii) that Cu+ ions improve tolerance towards Cd2 +, demonstrating thus that metal mixtures could also represent a selective advantage in the environment.
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Affiliation(s)
- Anne Soisig Steunou
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Anne Durand
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Marie-Line Bourbon
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Marion Babot
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Reem Tambosi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Sylviane Liotenberg
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Soufian Ouchane
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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Yang C, Ho YN, Makita R, Inoue C, Chien MF. Cupriavidus basilensis strain r507, a toxic arsenic phytoextraction facilitator, potentiates the arsenic accumulation by Pteris vittata. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 190:110075. [PMID: 31881405 DOI: 10.1016/j.ecoenv.2019.110075] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 12/07/2019] [Accepted: 12/07/2019] [Indexed: 06/10/2023]
Abstract
As a toxic and carcinogenic metalloid, arsenic has posed serious threat to human health. Phytoremediation has emerged as a promising approach to circumvent this problem. Arsenic uptake by Pteris vittata is largely determined by arsenic speciation and mainly occurs via roots; thus, rhizospheric microbial activities may play a key role in arsenic accumulation. The aim of this study was to investigate the potential of arsenic resistant rhizobacteria to enhance arsenic phytoextraction. A total of 49 cultivable rhizobacteria were isolated from the arsenic hyperaccumulating fern, Pteris vittata, and subjected to an initial analysis to identify potentially useful traits for arsenic phytoextraction, such as arsenic resistance and the presence of aioA(aroA)-like (arsenite oxidase-like) gene. Isolated strain r507, named as Cupriavidus basilensis strain r507, was a selected candidate for its outstanding arsenic tolerance, rapid arsenite oxidation ability, and strong colonization to P. vittata. Strain r507 was used in co-cultivation trials with P. vittata in the field for six months. Results showed that the inoculation with strain r507 potentiated As accumulation of P. vittata up to 171%. Molecular analysis confirmed that the inoculation increased the abundance of aioA-like genes in the rhizosphere, which might have facilitated arsenite oxidation and absorption. The findings of this study suggested the feasibility of co-cultivating hyperaccumulators with facilitator bacteria for practical arsenic phytoremediation.
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Affiliation(s)
- Chongyang Yang
- Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba-ku, 6-6-20 Aoba, Sendai, 980-8579, Japan
| | - Ying-Ning Ho
- Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba-ku, 6-6-20 Aoba, Sendai, 980-8579, Japan; Institute of Marine Biology and Center of Excellence for the Oceans, National Taiwan Ocean University, 2 Pei-Ning Road, Keelung, 20224, Taiwan
| | - Ryota Makita
- Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba-ku, 6-6-20 Aoba, Sendai, 980-8579, Japan
| | - Chihiro Inoue
- Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba-ku, 6-6-20 Aoba, Sendai, 980-8579, Japan
| | - Mei-Fang Chien
- Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba-ku, 6-6-20 Aoba, Sendai, 980-8579, Japan.
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Antoine R, Rivera-Millot A, Roy G, Jacob-Dubuisson F. Relationships Between Copper-Related Proteomes and Lifestyles in β Proteobacteria. Front Microbiol 2019; 10:2217. [PMID: 31608037 PMCID: PMC6769254 DOI: 10.3389/fmicb.2019.02217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 09/11/2019] [Indexed: 12/25/2022] Open
Abstract
Copper is an essential transition metal whose redox properties are used for a variety of enzymatic oxido-reductions and in electron transfer chains. It is also toxic to living beings, and therefore its cellular concentration must be strictly controlled. We have performed in silico analyses of the predicted proteomes of more than one hundred species of β proteobacteria to characterize their copper-related proteomes, including cuproproteins, i.e., proteins with active-site copper ions, copper chaperones, and copper-homeostasis systems. Copper-related proteomes represent between 0 and 1.48% of the total proteomes of β proteobacteria. The numbers of cuproproteins are globally proportional to the proteome sizes in all phylogenetic groups and strongly linked to aerobic respiration. In contrast, environmental bacteria have considerably larger proportions of copper-homeostasis systems than the other groups of bacteria, irrespective of their proteome sizes. Evolution toward commensalism, obligate, host-restricted pathogenesis or symbiosis is globally reflected in the loss of copper-homeostasis systems. In endosymbionts, defense systems and copper chaperones have disappeared, whereas residual cuproenzymes are electron transfer proteins for aerobic respiration. Lifestyle is thus a major determinant of the size and composition of the copper-related proteome, and it is particularly reflected in systems involved in copper homeostasis. Analyses of the copper-related proteomes of a number of species belonging to the Burkholderia, Bordetella, and Neisseria genera indicates that commensals are in the process of shedding their copper-homeostasis systems and chaperones to greater extents yet than pathogens.
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Affiliation(s)
| | | | | | - Françoise Jacob-Dubuisson
- Université de Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – Center for Infection and Immunity of Lille, Lille, France
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Cupriavidus sp. strain Ni-2 resistant to high concentration of nickel and its genes responsible for the tolerance by genome comparison. Arch Microbiol 2019; 201:1323-1331. [DOI: 10.1007/s00203-019-01700-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 10/26/2022]
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Gutiérrez-Barranquero JA, Cazorla FM, de Vicente A. Pseudomonas syringae pv. syringae Associated With Mango Trees, a Particular Pathogen Within the "Hodgepodge" of the Pseudomonas syringae Complex. FRONTIERS IN PLANT SCIENCE 2019; 10:570. [PMID: 31139201 PMCID: PMC6518948 DOI: 10.3389/fpls.2019.00570] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/15/2019] [Indexed: 05/29/2023]
Abstract
The Pseudomonas syringae complex comprises different genetic groups that include strains from both agricultural and environmental habitats. This complex group has been used for decades as a "hodgepodge," including many taxonomically related species. More than 60 pathovars of P. syringae have been described based on distinct host ranges and disease symptoms they cause. These pathovars cause disease relying on an array of virulence mechanisms. However, P. syringae pv. syringae (Pss) is the most polyphagous bacterium in the P. syringae complex, based on its wide host range, that primarily affects woody and herbaceous host plants. In early 1990s, bacterial apical necrosis (BAN) of mango trees, a critical disease elicited by Pss in Southern Spain was described for the first time. Pss exhibits important epiphytic traits and virulence factors, which may promote its survival and pathogenicity in mango trees and in other plant hosts. Over more than two decades, Pss strains isolated from mango trees have been comprehensively investigated to elucidate the mechanisms that governs their epiphytic and pathogenic lifestyles. In particular, the vast majority of Pss strains isolated from mango trees produce an antimetabolite toxin, called mangotoxin, whose leading role in virulence has been clearly demonstrated. Moreover, phenotypic, genetic and phylogenetic approaches support that Pss strains producers of BAN symptoms on mango trees all belong to a single phylotype within phylogroup 2, are adapted to the mango host, and produce mangotoxin. Remarkably, a genome sequencing project of the Pss model strain UMAF0158 revealed the presence of other factors that may play major roles in its different lifestyles, such as the presence of two different type III secretion systems, two type VI secretion systems and an operon for cellulose biosynthesis. The role of cellulose in increasing mango leaf colonization and biofilm formation, and impairing virulence of Pss, suggests that cellulose may play a pivotal role with regards to the balance of its different lifestyles. In addition, 62-kb plasmids belonging to the pPT23A-family of plasmids (PFPs) have been strongly associated with Pss strains that inhabit mango trees. Further, complete sequence and comparative genomic analyses revealed major roles of PFPs in detoxification of copper compounds and ultraviolet radiation resistance, both improving the epiphytic lifestyle of Pss on mango surfaces. Hence, in this review we summarize the research that has been conducted on Pss by our research group to elucidate the molecular mechanisms that underpin the epiphytic and pathogenic lifestyle on mango trees. Finally, future directions in this particular plant-pathogen story are discussed.
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Große C, Poehlein A, Blank K, Schwarzenberger C, Schleuder G, Herzberg M, Nies DH. The third pillar of metal homeostasis inCupriavidus metalliduransCH34: preferences are controlled by extracytoplasmic function sigma factors. Metallomics 2019; 11:291-316. [DOI: 10.1039/c8mt00299a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
InC. metallidurans, a network of 11 extracytoplasmic function sigma factors forms the third pillar of metal homeostasis acting in addition to the metal transportome and metal repositories as the first and second pillar.
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Affiliation(s)
- Cornelia Große
- Molecular Microbiology
- Martin-Luther-University Halle-Wittenberg
- Kurt-Mothes-Str. 3
- 06099 Halle (Saale)
- Germany
| | - Anja Poehlein
- Göttingen Genomics Laboratory
- Georg-August-University Göttingen, Grisebachstr. 8
- 37077 Göttingen
- Germany
| | - Kathrin Blank
- Molecular Microbiology
- Martin-Luther-University Halle-Wittenberg
- Kurt-Mothes-Str. 3
- 06099 Halle (Saale)
- Germany
| | - Claudia Schwarzenberger
- Molecular Microbiology
- Martin-Luther-University Halle-Wittenberg
- Kurt-Mothes-Str. 3
- 06099 Halle (Saale)
- Germany
| | - Grit Schleuder
- Molecular Microbiology
- Martin-Luther-University Halle-Wittenberg
- Kurt-Mothes-Str. 3
- 06099 Halle (Saale)
- Germany
| | - Martin Herzberg
- Molecular Microbiology
- Martin-Luther-University Halle-Wittenberg
- Kurt-Mothes-Str. 3
- 06099 Halle (Saale)
- Germany
| | - Dietrich H. Nies
- Molecular Microbiology
- Martin-Luther-University Halle-Wittenberg
- Kurt-Mothes-Str. 3
- 06099 Halle (Saale)
- Germany
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Abstract
Metals and metalloids have been used alongside antibiotics in livestock production for a long time. The potential and acute negative impact on the environment and human health of these livestock feed supplements has prompted lawmakers to ban or discourage the use of some or all of these supplements. This article provides an overview of current use in the European Union and the United States, detected metal resistance determinants, and the proteins and mechanisms responsible for conferring copper and zinc resistance in bacteria. A detailed description of the most common copper and zinc metal resistance determinants is given to illustrate not only the potential danger of coselecting antibiotic resistance genes but also the potential to generate bacterial strains with an increased potential to be pathogenic to humans. For example, the presence of a 20-gene copper pathogenicity island is highlighted since bacteria containing this gene cluster could be readily isolated from copper-fed pigs, and many pathogenic strains, including Escherichia coli O104:H4, contain this potential virulence factor, suggesting a potential link between copper supplements in livestock and the evolution of pathogens.
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Silver and Copper Acute Effects on Membrane Proteins and Impact on Photosynthetic and Respiratory Complexes in Bacteria. mBio 2018; 9:mBio.01535-18. [PMID: 30459190 PMCID: PMC6247083 DOI: 10.1128/mbio.01535-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The use of metal ions represents a serious threat to the environment and to all living organisms because of the acute toxicity of these ions. Nowadays, silver nanoparticles are one of the most widely used nanoparticles in various industrial and health applications. The antimicrobial effect of nanoparticles is in part related to the released Ag+ ions and their ability to interact with bacterial membranes. Here, we identify, both in vitro and in vivo, specific targets of Ag+ ions within the membrane of bacteria. This include complexes involved in photosynthesis, but also complexes involved in respiration. Silver (Ag+) and copper (Cu+) ions have been used for centuries in industry, as well as antimicrobial agents in agriculture and health care. Nowadays, Ag+ is also widely used in the field of nanotechnology. Yet, the underlying mechanisms driving toxicity of Ag+ ions in vivo are poorly characterized. It is well known that exposure to excess metal impairs the photosynthetic apparatus of plants and algae. Here, we show that the light-harvesting complex II (LH2) is the primary target of Ag+ and Cu+ exposure in the purple bacterium Rubrivivax gelatinosus. Ag+ and Cu+ specifically inactivate the 800-nm absorbing bacteriochlorophyll a (B800), while Ni2+ or Cd2+ treatment had no effect. This was further supported by analyses of CuSO4- or AgNO3-treated membrane proteins. Indeed, this treatment induced changes in the LH2 absorption spectrum related to the disruption of the interaction of B800 molecules with the LH2 protein. This caused the release of B800 molecules and subsequently impacted the spectral properties of the carotenoids within the 850-nm absorbing LH2. Moreover, previous studies have suggested that Ag+ can affect the respiratory chain in mitochondria and bacteria. Our data demonstrated that exposure to Ag+, both in vivo and in vitro, caused a decrease of cytochrome c oxidase and succinate dehydrogenase activities. Ag+ inhibition of these respiratory complexes was also observed in Escherichia coli, but not in Bacillus subtilis.
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Fagorzi C, Checcucci A, diCenzo GC, Debiec-Andrzejewska K, Dziewit L, Pini F, Mengoni A. Harnessing Rhizobia to Improve Heavy-Metal Phytoremediation by Legumes. Genes (Basel) 2018; 9:genes9110542. [PMID: 30413093 PMCID: PMC6266702 DOI: 10.3390/genes9110542] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/05/2018] [Accepted: 11/06/2018] [Indexed: 12/15/2022] Open
Abstract
Rhizobia are bacteria that can form symbiotic associations with plants of the Fabaceae family, during which they reduce atmospheric di-nitrogen to ammonia. The symbiosis between rhizobia and leguminous plants is a fundamental contributor to nitrogen cycling in natural and agricultural ecosystems. Rhizobial microsymbionts are a major reason why legumes can colonize marginal lands and nitrogen-deficient soils. Several leguminous species have been found in metal-contaminated areas, and they often harbor metal-tolerant rhizobia. In recent years, there have been numerous efforts and discoveries related to the genetic determinants of metal resistance by rhizobia, and on the effectiveness of such rhizobia to increase the metal tolerance of host plants. Here, we review the main findings on the metal resistance of rhizobia: the physiological role, evolution, and genetic determinants, and the potential to use native and genetically-manipulated rhizobia as inoculants for legumes in phytoremediation practices.
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Affiliation(s)
- Camilla Fagorzi
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy.
| | - Alice Checcucci
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy.
| | - George C diCenzo
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy.
| | - Klaudia Debiec-Andrzejewska
- Laboratory of Environmental Pollution Analysis, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
| | - Lukasz Dziewit
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
| | - Francesco Pini
- Department of Agri-food Production and Environmental Science, University of Florence, 50144 Florence, Italy.
| | - Alessio Mengoni
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy.
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Moser TH, Shokuhfar T, Evans JE. Considerations for imaging thick, low contrast, and beam sensitive samples with liquid cell transmission electron microscopy. Micron 2018; 117:8-15. [PMID: 30419433 DOI: 10.1016/j.micron.2018.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/15/2018] [Accepted: 10/29/2018] [Indexed: 01/08/2023]
Abstract
Transmission electron microscopy of whole cells is hindered by the inherently large thickness and low atomic contrast intrinsic of cellular material. Liquid cell transmission electron microscopy allows samples to remain in their native hydrated state and may permit visualizing cellular dynamics in-situ. However, imaging biological cells with this approach remains challenging and identifying an optimal imaging regime using empirical data would help foster new advancements in the field. Recent questions about the role of the electron beam inducing morphological changes or damaging cellular structure and function necessitates further investigation of electron beam-cell interactions, but such comparisons are complicated by variability in imaging techniques used across various studies currently present in literature. The necessity for using low electron fluxes while imaging biological samples requires finding an imaging strategy which produces the strongest contrast and signal to noise ratio for the electron flux used. Here, we experimentally measure and evaluate signal to noise ratios and damage mechanisms between liquid and cryogenic samples of intact cells using multiple electron imaging modalities all on the same instrument and with equivalent beam parameters to standardize the comparison. We also discuss considerations for optimal electron microscopy imaging conditions for future studies on whole cells within liquid environments.
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Affiliation(s)
- Trevor H Moser
- Environmental Molecular Sciences Laboratory, 3335 Innovation Blvd., Richland, WA 99354, USA; Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931, USA
| | - Tolou Shokuhfar
- Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931, USA; University of Illinois Chicago, 1200 W. Harrison St., Chicago, IL 60607, USA
| | - James E Evans
- Environmental Molecular Sciences Laboratory, 3335 Innovation Blvd., Richland, WA 99354, USA; School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA.
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Gallagher AL, Miller SR. Expression of Novel Gene Content Drives Adaptation to Low Iron in the Cyanobacterium Acaryochloris. Genome Biol Evol 2018; 10:1484-1492. [PMID: 29850825 PMCID: PMC6007379 DOI: 10.1093/gbe/evy099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2018] [Indexed: 12/24/2022] Open
Abstract
Variation in genome content is a potent mechanism of microbial adaptation. The genomes of members of the cyanobacterial genus Acaryochloris vary greatly in gene content as a consequence of the idiosyncratic retention of both recent gene duplicates and plasmid-encoded genes acquired by horizontal transfer. For example, the genome of Acaryochloris strain MBIC11017, which was isolated from an iron-limited environment, is enriched in duplicated and novel genes involved in iron assimilation. Here, we took an integrative approach to characterize the adaptation of Acaryochloris MBIC11017 to low environmental iron availability and the relative contributions of the expression of duplicated versus novel genes. We observed that Acaryochloris MBIC11017 grew faster and to a higher yield in the presence of nanomolar concentrations of iron than did a closely related strain. These differences were associated with both a higher rate of iron assimilation and a greater abundance of iron assimilation transcripts. However, recently duplicated genes contributed little to increased transcript dosage; rather, the maintenance of these duplicates in the MBIC11017 genome is likely due to the sharing of ancestral dosage by expression reduction. Instead, novel, horizontally transferred genes are responsible for the differences in transcript abundance. The study provides insights on the mechanisms of adaptive genome evolution and gene expression in Acaryochloris.
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Affiliation(s)
| | - Scott R Miller
- Division of Biological Sciences, The University of Montana
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Flores O, Prince C, Nuñez M, Vallejos A, Mardones C, Yañez C, Besoain X, Bastías R. Genetic and Phenotypic Characterization of Indole-Producing Isolates of Pseudomonas syringae pv. actinidiae Obtained From Chilean Kiwifruit Orchards. Front Microbiol 2018; 9:1907. [PMID: 30186252 PMCID: PMC6113925 DOI: 10.3389/fmicb.2018.01907] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 07/30/2018] [Indexed: 12/29/2022] Open
Abstract
In recent years, Chilean kiwifruit production has been affected by the phytopathogen Pseudomonas syringae pv. actinidiae (Psa), which has caused losses to the industry. In this study, we report the genotypic and phenotypic characterization of 18 Psa isolates obtained from Chilean kiwifruits orchards between 2012 and 2016 from different geographic origins. Genetic analysis by multilocus sequence analysis (MLSA) using four housekeeping genes (gyrB, rpoD, gltA, and gapA) and the identification of type III effector genes suggest that the Chilean Psa isolates belong to the Psa Biovar 3 cluster. All of the isolates were highly homogenous in regard to their phenotypic characteristics. None of the isolates were able to form biofilms over solid plastic surfaces. However, all of the isolates formed cellular aggregates in the air-liquid interface. All of the isolates, except for Psa 889, demonstrated swimming motility, while only isolate Psa 510 demonstrated swarming motility. The biochemical profiles of the isolates revealed differences in 22% of the tests in at least one Psa isolate when analyzed with the BIOLOG system. Interestingly, all of the isolates were able to produce indole using a tryptophan-dependent pathway. PCR analysis revealed the presence of the genes aldA/aldB and iaaL/matE, which are associated with the production of indole-3-acetic acid (IAA) and indole-3-acetyl-3-L-lysine (IAA-Lys), respectively, in P. syringae. In addition, IAA was detected in the cell free supernatant of a representative Chilean Psa strain. This work represents the most extensive analysis in terms of the time and geographic origin of Chilean Psa isolates. To our knowledge, this is the first report of Psa being able to produce IAA. Further studies are needed to determine the potential role of IAA in the virulence of Psa during kiwifruit infections and whether this feature is observed in other Psa biovars.
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Affiliation(s)
- Oriana Flores
- Laboratorio de Microbiología, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Camila Prince
- Laboratorio de Microbiología, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Mauricio Nuñez
- Laboratorio de Microbiología, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Alejandro Vallejos
- Departamento de Análisis Instrumental, Facultad de Farmacia, Universidad de Concepción, Concepción, Chile
| | - Claudia Mardones
- Departamento de Análisis Instrumental, Facultad de Farmacia, Universidad de Concepción, Concepción, Chile
| | - Carolina Yañez
- Laboratorio de Microbiología, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Ximena Besoain
- Laboratorio de Fitopatología, Escuela de Agronomía, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Roberto Bastías
- Laboratorio de Microbiología, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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Peng J, Miao L, Chen X, Liu P. Comparative Transcriptome Analysis of Pseudomonas putida KT2440 Revealed Its Response Mechanisms to Elevated Levels of Zinc Stress. Front Microbiol 2018; 9:1669. [PMID: 30087671 PMCID: PMC6066579 DOI: 10.3389/fmicb.2018.01669] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 07/04/2018] [Indexed: 01/03/2023] Open
Abstract
The whole-genome transcriptional response of Pseudomonas putida KT2440 to stress-inducing concentrations of zinc was analyzed in this study by RNA sequencing to thoroughly investigate the bacterial cell response to zinc toxicity. The data revealed that different levels of zinc stress strongly affected the transcription of genes from the following categories: metal transport genes, genes involved in membrane homeostasis, oxidative-stress-responding genes, and genes associated with basic cellular metabolism. At the lowest zinc dose, only several genes associated with metal transport and membrane homeostasis were strongly influenced. At the intermediate zinc dose, transcriptional changes of genes belonging to these two categories were highly pronounced. In addition, the intermediate zinc stress produced high levels of oxidative stress, and influenced amino acid metabolism and respiratory chains of P. putida. At the highest zinc dose, the induction of genes responsible for Fe–S cluster biogenesis was the most remarkable feature. Moreover, upregulation of glyoxylate cycle was observed. In summary, the adaptation of the cell envelope, the maintenance of metal homeostasis and intracellular redox status, and the transcriptional control of metabolism are the main elements of stress response, which facilitates the survival of P. putida KT2440 in zinc-polluted environments.
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Affiliation(s)
- Jun Peng
- College of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan, China
| | - Lihong Miao
- College of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan, China
| | - Xi Chen
- Wuhan Institute of Virology, Chinese Academy of Science, Wuhan, China
| | - Pulin Liu
- College of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan, China
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Cvetkovska M, Szyszka-Mroz B, Possmayer M, Pittock P, Lajoie G, Smith DR, Hüner NPA. Characterization of photosynthetic ferredoxin from the Antarctic alga Chlamydomonas sp. UWO241 reveals novel features of cold adaptation. THE NEW PHYTOLOGIST 2018; 219:588-604. [PMID: 29736931 DOI: 10.1111/nph.15194] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 03/27/2018] [Indexed: 06/08/2023]
Abstract
The objective of this work was to characterize photosynthetic ferredoxin from the Antarctic green alga Chlamydomonas sp. UWO241, a key enzyme involved in distributing photosynthetic reducing power. We hypothesize that ferredoxin possesses characteristics typical of cold-adapted enzymes, namely increased structural flexibility and high activity at low temperatures, accompanied by low stability at moderate temperatures. To address this objective, we purified ferredoxin from UWO241 and characterized the temperature dependence of its enzymatic activity and protein conformation. The UWO241 ferredoxin protein, RNA, and DNA sequences were compared with homologous sequences from related organisms. We provide evidence for the duplication of the main ferredoxin gene in the UWO241 nuclear genome and the presence of two highly similar proteins. Ferredoxin from UWO241 has both high activity at low temperatures and high stability at moderate temperatures, representing a novel class of cold-adapted enzymes. Our study reveals novel insights into how photosynthesis functions in the cold. The presence of two distinct ferredoxin proteins in UWO241 could provide an adaptive advantage for survival at cold temperatures. The primary amino acid sequence of ferredoxin is highly conserved among photosynthetic species, and we suggest that subtle differences in sequence can lead to significant changes in activity at low temperatures.
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Affiliation(s)
- Marina Cvetkovska
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University ofWestern Ontario, London, ON, N6A 5B7, Canada
| | - Beth Szyszka-Mroz
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University ofWestern Ontario, London, ON, N6A 5B7, Canada
| | - Marc Possmayer
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University ofWestern Ontario, London, ON, N6A 5B7, Canada
| | - Paula Pittock
- Department of Biochemistry and Biological Mass Spectrometry Laboratory, University of Western Ontario, London, ON, N6G 2V4, Canada
| | - Gilles Lajoie
- Department of Biochemistry and Biological Mass Spectrometry Laboratory, University of Western Ontario, London, ON, N6G 2V4, Canada
| | - David R Smith
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University ofWestern Ontario, London, ON, N6A 5B7, Canada
| | - Norman P A Hüner
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University ofWestern Ontario, London, ON, N6A 5B7, Canada
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Abstract
Copper-binding metallophores, or chalkophores, play a role in microbial copper homeostasis that is analogous to that of siderophores in iron homeostasis. The best-studied chalkophores are members of the methanobactin (Mbn) family-ribosomally produced, posttranslationally modified natural products first identified as copper chelators responsible for copper uptake in methane-oxidizing bacteria. To date, Mbns have been characterized exclusively in those species, but there is genomic evidence for their production in a much wider range of bacteria. This review addresses the current state of knowledge regarding the function, biosynthesis, transport, and regulation of Mbns. While the roles of several proteins in these processes are supported by substantial genetic and biochemical evidence, key aspects of Mbn manufacture, handling, and regulation remain unclear. In addition, other natural products that have been proposed to mediate copper uptake as well as metallophores that have biologically relevant roles involving copper binding, but not copper uptake, are discussed.
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Affiliation(s)
- Grace E Kenney
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA; ,
| | - Amy C Rosenzweig
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA; ,
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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46
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Park JH, Kim SJ, Ahn JS, Lim DH, Han YS. Mobility of multiple heavy metalloids in contaminated soil under various redox conditions: Effects of iron sulfide presence and phosphate competition. CHEMOSPHERE 2018; 197:344-352. [PMID: 29407804 DOI: 10.1016/j.chemosphere.2018.01.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/09/2018] [Accepted: 01/14/2018] [Indexed: 06/07/2023]
Abstract
The mobility of heavy metalloids including As, Sb, Mo, W, and Cr in soil was investigated under both reducing and oxidizing conditions. The effects of soil mineralogy and the presence of competitive anions were studied as important factors affecting the mobility of these contaminants. Batch experiments conducted with the addition of oxidized and fresh FeS exhibited enhanced sorption rates for As and W under oxidizing conditions, and for Mo under reducing conditions. The inhibitory effect of phosphate on the sorption rates was most apparent for As and Mo under both oxidizing and reducing conditions, while only a small phosphate effect was observed for Sb and W. For Sb and W mobility, pH was determined to be the most important controlling factor. The results of long-term batch experiments revealed that differences in the mobility of metalloids, particularly As, were also influenced by microbial activity in the oxidizing and reducing conditions.
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Affiliation(s)
- Ji-Hyun Park
- Korea Institute of Geoscience and Mineral Resources (KIGAM), Republic of Korea; Department of Environmental Engineering, Chungbuk National University, Republic of Korea
| | - So-Jeong Kim
- Korea Institute of Geoscience and Mineral Resources (KIGAM), Republic of Korea
| | - Joo Sung Ahn
- Korea Institute of Geoscience and Mineral Resources (KIGAM), Republic of Korea
| | - Dong-Hee Lim
- Department of Environmental Engineering, Chungbuk National University, Republic of Korea
| | - Young-Soo Han
- Korea Institute of Geoscience and Mineral Resources (KIGAM), Republic of Korea.
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Gonzalez MR, Ducret V, Leoni S, Perron K. Pseudomonas aeruginosa zinc homeostasis: Key issues for an opportunistic pathogen. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:722-733. [PMID: 29410128 DOI: 10.1016/j.bbagrm.2018.01.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 01/26/2018] [Indexed: 12/13/2022]
Abstract
Zinc is an essential trace element for almost all living organisms. In the opportunistic bacterial pathogen Pseudomonas aeruginosa, zinc has been shown to play an important role in virulence, in colonization of the host organism and has also been shown to be involved in antibiotic resistance. P. aeruginosa possesses numerous systems enabling it to thrive in zinc-depleted conditions as well as high-zinc situations, two environments that are encountered during human infection. These capabilities account for its pathogenic strength. The main aim of this review is to focus on zinc homeostasis in P. aeruginosa and the genetic regulation of the systems involved. The interconnection with virulence, as well as the mechanism of co-regulation between metal and antibiotic resistance, are of prime interest for understanding the molecular mechanisms allowing P. aeruginosa to switch from its existence as a common environmental bacterium to a severe opportunistic pathogen. This article is part of a Special Issue entitled: Dynamic gene expression, edited by Prof. Patrick Viollier.
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Affiliation(s)
- Manuel R Gonzalez
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Verena Ducret
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Sara Leoni
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Karl Perron
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland; School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva, Switzerland.
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48
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Punjee P, Siripornadulsil W, Siripornadulsil S. Reduction of cadmium uptake in rice endophytically colonized with the cadmium-tolerant bacterium Cupriavidus taiwanensis KKU2500-3. Can J Microbiol 2018; 64:131-145. [DOI: 10.1139/cjm-2017-0198] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of the cadmium (Cd)-tolerant bacterium Cupriavidus taiwanensis KKU2500-3 on the growth, yield, and Cd concentration in rice grains were investigated in the rice variety Phitsanulok 2 (PL2), which was cultivated in a hydroponic greenhouse. The numbers of Cd-tolerant bacteria isolated from the roots and shoots of plants under the RB (rice with bacteria) and RBC (rice with bacteria and Cd) treatments ranged from 2.60 to 9.03 and from 3.99 to 9.60 log cfu·g−1 of PL2, respectively. This KKU2500-3 strain was successfully colonized in rice, indicating that it was not only nontoxic to the plants but also became distributed and reproduced throughout the plants. Scanning electron microscopy analysis revealed attachment of the bacterium to the root surface, whereas the internally colonized bacteria were located in the vascular tissue, cell wall, and intercellular space. Although the Cd contents found in PL2 were very high (189.10 and 79.49 mg·kg−1 in the RC (rice with Cd) and RBC roots, respectively), the Cd accumulated inside the rice seeds at densities of only 3.10 and 1.31 mg·kg−1, respectively; thus, the bacteria reduced the Cd content to 57.74% of the control content. Therefore, the colonizing bacteria likely acted as an inhibitor of Cd translocation in PL2.
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Affiliation(s)
- Putthita Punjee
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Wilailak Siripornadulsil
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
- Research Center for Environmental and Hazardous Substance Management, Khon Kaen University, Khon Kaen, Thailand
| | - Surasak Siripornadulsil
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
- Research Center for Environmental and Hazardous Substance Management, Khon Kaen University, Khon Kaen, Thailand
- Genomics and Proteomics Research Group for Improvement of Salt-tolerant Rice, Khon Kaen University, Khon Kaen, Thailand
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49
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Synergistic Toxicity of Copper and Gold Compounds in Cupriavidus metallidurans. Appl Environ Microbiol 2017; 83:AEM.01679-17. [PMID: 28939602 DOI: 10.1128/aem.01679-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/12/2017] [Indexed: 11/20/2022] Open
Abstract
The bacterium Cupriavidus metallidurans can reduce toxic gold(I/III) complexes and biomineralize them into metallic gold (Au) nanoparticles, thereby mediating the (trans)formation of Au nuggets. In Au-rich soils, most transition metals do not interfere with the resistance of this bacterium to toxic mobile Au complexes and can be removed from the cell by plasmid-encoded metal efflux systems. Copper is a noticeable exception: the presence of Au complexes and Cu ions results in synergistic toxicity, which is accompanied by an increased cytoplasmic Cu content and formation of Au nanoparticles in the periplasm. The periplasmic Cu-oxidase CopA was not essential for formation of the periplasmic Au nanoparticles. As shown with the purified and reconstituted Cu efflux system CupA, Au complexes block Cu-dependent release of phosphate from ATP by CupA, indicating inhibition of Cu transport. Moreover, Cu resistance of Au-inhibited cells was similar to that of mutants carrying deletions in the genes for the Cu-exporting PIB1-type ATPases. Consequently, Au complexes inhibit export of cytoplasmic Cu ions, leading to an increased cellular Cu content and decreased Cu and Au resistance. Uncovering the biochemical mechanisms of synergistic Au and Cu toxicity in C. metallidurans explains the issues this bacterium has to face in auriferous environments, where it is an important contributor to the environmental Au cycle.IMPORTANCE C. metallidurans lives in metal-rich environments, including auriferous soils that contain a mixture of toxic transition metal cations. We demonstrate here that copper ions and gold complexes exert synergistic toxicity because gold ions inhibit the copper-exporting P-type ATPase CupA, which is central to copper resistance in this bacterium. Such a situation should occur in soils overlying Au deposits, in which Cu/Au ratios usually are ≫1. Appreciating how C. metallidurans solves the problem of living in environments that contain both Au and Cu is a prerequisite to understand the molecular mechanisms underlying gold cycling in the environment, and the significance and opportunities of microbiota for specific targeting to Au in mineral exploration and ore processing.
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50
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Nies DH. The biological chemistry of the transition metal "transportome" of Cupriavidus metallidurans. Metallomics 2017; 8:481-507. [PMID: 27065183 DOI: 10.1039/c5mt00320b] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review tries to illuminate how the bacterium Cupriavidus metallidurans CH34 is able to allocate essential transition metal cations to their target proteins although these metals have similar charge-to-surface ratios and chemical features, exert toxic effects, compete with each other, and occur in the bacterial environment over a huge range of concentrations and speciations. Central to this ability is the "transportome", the totality of all interacting metal import and export systems, which, as an emergent feature, transforms the environmental metal content and speciation into the cellular metal mélange. In a kinetic flow equilibrium resulting from controlled uptake and efflux reactions, the periplasmic and cytoplasmic metal content is adjusted in a way that minimizes toxic effects. A central core function of the transportome is to shape the metal ion composition using high-rate and low-specificity reactions to avoid time and/or energy-requiring metal discrimination reactions. This core is augmented by metal-specific channels that may even deliver metals all the way from outside of the cell to the cytoplasm. This review begins with a description of the basic chemical features of transition metal cations and the biochemical consequences of these attributes, and which transition metals are available to C. metallidurans. It then illustrates how the environment influences the metal content and speciation, and how the transportome adjusts this metal content. It concludes with an outlook on the fate of metals in the cytoplasm. By generalization, insights coming from C. metallidurans shed light on multiple transition metal homoeostatic mechanisms in all kinds of bacteria including pathogenic species, where the "battle" for metals is an important part of the host-pathogen interaction.
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Affiliation(s)
- Dietrich H Nies
- Molecular Microbiology, Institute for Biology/Microbiology, Martin-Luther-University Halle-Wittenberg, Germany.
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