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Tang X, Zeng G, Fan C, Zhou M, Tang L, Zhu J, Wan J, Huang D, Chen M, Xu P, Zhang C, Lu Y, Xiong W. Chromosomal expression of CadR on Pseudomonas aeruginosa for the removal of Cd(II) from aqueous solutions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 636:1355-1361. [PMID: 29913596 DOI: 10.1016/j.scitotenv.2018.04.229] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/13/2018] [Accepted: 04/17/2018] [Indexed: 05/08/2023]
Abstract
Genetically engineered bacteria for pollution control of heavy metal have been widely studied, however, using Pseudomonas aeruginosa (P. aeruginosa) that can adapt to various circumstances to remediate heavy metal pollution is rarely reported. In this study, we employed CadR, a cadmium (Cd)-specific binding protein, displaying on the surface of P. aeruginosa with chromosomal expression. The genetically engineered (GE) P. aeruginosa still flourished in the 30th generation in the LB broth which contained 100 μM Cd(II), exhibiting an excellent genetic stability. Chromosomally expressed P. aeruginosa showed an adsorption capacity of up to 131.9 μmol/g of Cd(II). In addition, the low concentration of the coexisting two valence ions has no significant effect on adsorption capacity of Cd(II). This study provides a direction for application of P. aeruginosa in environment remediation.
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Affiliation(s)
- Xiang Tang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China.
| | - Changzheng Fan
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China.
| | - Man Zhou
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Lin Tang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Jingjing Zhu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Jia Wan
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Danlian Huang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Ming Chen
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Piao Xu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Chen Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Yue Lu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Weiping Xiong
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
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Milan M, Carraro L, Fariselli P, Martino ME, Cavalieri D, Vitali F, Boffo L, Patarnello T, Bargelloni L, Cardazzo B. Microbiota and environmental stress: how pollution affects microbial communities in Manila clams. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 194:195-207. [PMID: 29202271 DOI: 10.1016/j.aquatox.2017.11.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/13/2017] [Accepted: 11/26/2017] [Indexed: 06/07/2023]
Abstract
Given the crucial role of microbiota in host development, health, and environmental interactions, genomic analyses focusing on host-microbiota interactions should certainly be considered in the investigation of the adaptive mechanisms to environmental stress. Recently, several studies suggested that microbiota associated to digestive tract is a key, although still not fully understood, player that must be considered to assess the toxicity of environmental contaminants. Bacteria-dependent metabolism of xenobiotics may indeed modulate the host toxicity. Conversely, environmental variables (including pollution) may alter the microbial community and/or its metabolic activity leading to host physiological alterations that may contribute to their toxicity. Here, 16s rRNA gene amplicon sequencing has been applied to characterize the hepatopancreas microbiota composition of the Manila clam, Ruditapes philippinarum. The animals were collected in the Venice lagoon area, which is subject to different anthropogenic pressures, mainly represented by the industrial activities of Porto Marghera (PM). Seasonal and geographic differences in clam microbiotas were explored and linked to host response to chemical stress identified in a previous study at the transcriptome level, establishing potential interactions among hosts, microbes, and environmental parameters. The obtained results showed the recurrent presence of putatively detoxifying bacterial taxa in PM clams during winter and over-representation of several metabolic pathways involved in xenobiotic degradation, which suggested the potential for host-microbial synergistic detoxifying actions. Strong interaction between seasonal and chemically-induced responses was also observed, which partially obscured such potentially synergistic actions. Seasonal variables and exposure to toxicants were therefore shown to interact and substantially affect clam microbiota, which appeared to mirror host response to environmental variation. It is clear that understanding how animals respond to chemical stress cannot ignore a key component of such response, the microbiota.
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Affiliation(s)
- M Milan
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020, Legnaro, Italy; CONISMA - Consorzio Nazionale Interuniversitario per le Scienze del Mare, Roma, Italy
| | - L Carraro
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020, Legnaro, Italy
| | - P Fariselli
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020, Legnaro, Italy
| | - M E Martino
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Ecole Normale Supérieure de Lyon, CNRS UMR 5242, Université Claude Bernard Lyon, Lyon, France
| | - D Cavalieri
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Firenze, Italy
| | - F Vitali
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Firenze, Italy
| | - L Boffo
- Associazione "Vongola Verace di Chioggia", Italy
| | - T Patarnello
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020, Legnaro, Italy
| | - L Bargelloni
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020, Legnaro, Italy; CONISMA - Consorzio Nazionale Interuniversitario per le Scienze del Mare, Roma, Italy
| | - B Cardazzo
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020, Legnaro, Italy
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53
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Oliva-Arancibia B, Órdenes-Aenishanslins N, Bruna N, Ibarra PS, Zacconi FC, Pérez-Donoso JM, Poblete-Castro I. Co-synthesis of medium-chain-length polyhydroxyalkanoates and CdS quantum dots nanoparticles in Pseudomonas putida KT2440. J Biotechnol 2017; 264:29-37. [PMID: 29056529 DOI: 10.1016/j.jbiotec.2017.10.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 10/17/2017] [Accepted: 10/18/2017] [Indexed: 12/15/2022]
Abstract
Microbial polymers and nanomaterials production is a promising alternative for sustainable bioeconomics. To this end, we used Pseudomonas putida KT2440 as a cell factory in batch cultures to coproduce two important nanotechnology materials- medium-chain-length (MCL)-polyhydroxyalkanoates (PHAs) and CdS fluorescent nanoparticles (i.e. quantum dots [QDots]). Due to high cadmium resistance, biomass and PHA yields were almost unaffected by coproduction conditions. Fluorescent nanocrystal biosynthesis was possible only in presence of cysteine. Furthermore, this process took place exclusively in the cell, displaying the classical emission spectra of CdS QDots under UV-light exposure. Cell fluorescence, zeta potential values, and particles size of QDots depended on cadmium concentration and exposure time. Using standard PHA-extraction procedures, the biosynthesized QDots remained associated with the biomass, and the resulting PHAs presented no traces of CdS QDots. Transmission electron microscopy located the synthesized PHAs in the cell cytoplasm, whereas CdS nanocrystals were most likely located within the periplasmic space, exhibiting no apparent interaction. This is the first report presenting the microbial coproduction of MCL-PHAs and CdS QDots in P. putida KT2440, thus constituting a foundation for further bioprocess developments and strain engineering towards the efficient synthesis of these highly relevant bioproducts for nanotechnology.
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Affiliation(s)
- Barbara Oliva-Arancibia
- Biosystems Engineering Laboratory, Center for Bioinformatics and Integrative Biology (CBIB), Faculty of Biological Sciences, Universidad Andres Bello, República 239, 8370146 Santiago, Chile
| | - Nicolás Órdenes-Aenishanslins
- BioNanotechnology and Microbiology Laboratory, Center for Bioinformatics and Integrative Biology (CBIB), Faculty of Biological Sciences, Universidad Andres Bello, República 239, 8370146 Santiago, Chile
| | - Nicolas Bruna
- BioNanotechnology and Microbiology Laboratory, Center for Bioinformatics and Integrative Biology (CBIB), Faculty of Biological Sciences, Universidad Andres Bello, República 239, 8370146 Santiago, Chile
| | - Paula S Ibarra
- Biosystems Engineering Laboratory, Center for Bioinformatics and Integrative Biology (CBIB), Faculty of Biological Sciences, Universidad Andres Bello, República 239, 8370146 Santiago, Chile
| | - Flavia C Zacconi
- Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul, 78204336 Santiago, Chile
| | - José M Pérez-Donoso
- BioNanotechnology and Microbiology Laboratory, Center for Bioinformatics and Integrative Biology (CBIB), Faculty of Biological Sciences, Universidad Andres Bello, República 239, 8370146 Santiago, Chile
| | - Ignacio Poblete-Castro
- Biosystems Engineering Laboratory, Center for Bioinformatics and Integrative Biology (CBIB), Faculty of Biological Sciences, Universidad Andres Bello, República 239, 8370146 Santiago, Chile.
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Bereza-Malcolm L, Aracic S, Kannan R, Mann G, Franks AE. Functional characterization of Gram-negative bacteria from different genera as multiplex cadmium biosensors. Biosens Bioelectron 2017; 94:380-387. [PMID: 28319906 DOI: 10.1016/j.bios.2017.03.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 12/22/2022]
Abstract
Widespread presence of cadmium in soil and water systems is a consequence of industrial and agricultural processes. Subsequent accumulation of cadmium in food and drinking water can result in accidental consumption of dangerous concentrations. As such, cadmium environmental contamination poses a significant threat to human health. Development of microbial biosensors, as a novel alternative method for in situ cadmium detection, may reduce human exposure by complementing traditional analytical methods. In this study, a multiplex cadmium biosensing construct was assembled by cloning a single-output cadmium biosensor element, cadRgfp, and a constitutively expressed mrfp1 onto a broad-host range vector. Incorporation of the duplex fluorescent output [green and red fluorescence proteins] allowed measurement of biosensor functionality and viability. The biosensor construct was tested in several Gram-negative bacteria including Pseudomonas, Shewanella and Enterobacter. The multiplex cadmium biosensors were responsive to cadmium concentrations ranging from 0.01 to 10µgml-1, as well as several other heavy metals, including arsenic, mercury and lead at similar concentrations. The biosensors were also responsive within 20-40min following exposure to 3µgml-1 cadmium. This study highlights the importance of testing biosensor constructs, developed using synthetic biology principles, in different bacterial genera.
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Affiliation(s)
- Lara Bereza-Malcolm
- Applied and Environmental Microbiology Laboratory, Department of Physiology, Anatomy and Microbiology, La Trobe University, Plenty Road, Melbourne, Victoria 3086, Australia.
| | - Sanja Aracic
- Applied and Environmental Microbiology Laboratory, Department of Physiology, Anatomy and Microbiology, La Trobe University, Plenty Road, Melbourne, Victoria 3086, Australia.
| | - Ruban Kannan
- Applied and Environmental Microbiology Laboratory, Department of Physiology, Anatomy and Microbiology, La Trobe University, Plenty Road, Melbourne, Victoria 3086, Australia.
| | - Gülay Mann
- Land Division, Defence Science and Technology Group, Melbourne, Victoria 3207, Australia.
| | - Ashley E Franks
- Applied and Environmental Microbiology Laboratory, Department of Physiology, Anatomy and Microbiology, La Trobe University, Plenty Road, Melbourne, Victoria 3086, Australia.
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55
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de Alencar FLS, Navoni JA, do Amaral VS. The use of bacterial bioremediation of metals in aquatic environments in the twenty-first century: a systematic review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:16545-16559. [PMID: 28540556 DOI: 10.1007/s11356-017-9129-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/26/2017] [Indexed: 06/07/2023]
Abstract
Metal pollution is a current environmental issue as a consequence of unregulated anthropic activiy. A wide range of bioremediation strategies have been successfully implemented to recover contaminated areas. Among them, bacterial bioremediation stands out as a promising tool to confront these types of concerns. This study aimed to compare and discuss worldwide scientific evolution of bacterial potential for metal bioremediation in aquatic ecosystems. The study consisted of a systematic review, elaborated through a conceptual hypothesis model, during the period from 2000 to 2016, using PubMed, MEDLINE, and SciELO databases as data resources. The countries with the largest number of reports included in this work were India and the USA. Industrial wastewater discharge was the main subject associated to metal contamination/pollution and where bacterial bioremediations have mostly been applied. Biosorption is the main bioremediation mechanism described. Bacterial adaptation to metal presence was discussed in all the selected studies, and chromium was the most researched bioremedied substrate. Gram-negative Pseudomonas aeruginosas and the Gram-positive Bacillus subtilis bacteria were microorganisms with the greatest applicability for metal bioremediation. Most reports involved the study of genes and/or proteins related to metal metabolism and/or resistence, and Chromobacterium violaceum was the most studied. The present work shows the relevance of metal bacterial bioremediation through the high number of studies aimed at understanding the microbiological mechanisms involved. Moreover, the developed processes applied in removal and/or reducing the resulting environmental metal contaminant/pollutant load have become a current and increasingly biotechnological issue for recovering impacted areas.
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Affiliation(s)
| | - Julio Alejandro Navoni
- Development and Environment, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Viviane Souza do Amaral
- Development and Environment, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
- Department of Cell Biology and Genetics, Federal University of Rio Grande do Norte (UFRN), Natal, RN, Brazil.
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56
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Zhai Q, Xiao Y, Zhao J, Tian F, Zhang H, Narbad A, Chen W. Identification of key proteins and pathways in cadmium tolerance of Lactobacillus plantarum strains by proteomic analysis. Sci Rep 2017; 7:1182. [PMID: 28446769 PMCID: PMC5430759 DOI: 10.1038/s41598-017-01180-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/22/2017] [Indexed: 12/20/2022] Open
Abstract
Our previous study confirmed the protective potential of Lactobacillus plantarum (L. plantarum) strains in alleviation of cadmium (Cd) toxicity in vivo and demonstrated that the observed protection largely depended on the tolerance of the strains to Cd-induced stress. It was also observed that there were significant intra-species differences in Cd tolerance of L. plantarum strains. In this study, we investigated the mechanism of Cd induced stress response of L. plantarum strains using the isobaric tags for relative and absolute quantitation (iTRAQ) based comparative proteomics. L. plantarum CCFM8610 (strongly resistant to Cd) and L. plantarum CCFM191 (sensitive to Cd) were selected as target strains, and their proteomic profiles in the presence and absence of Cd exposure were compared. We propose that the underlying mechanism of the exceptional Cd tolerance of CCFM8610 may be attributed to the following: (a) a specific energy-conservation survival mode; (b) mild induction of its cellular defense and repair system; (c) an enhanced biosynthesis of hydrophobic amino acids in response to Cd; (d) inherent superior Cd binding ability and effective cell wall biosynthesis ability; (e) a tight regulation on ion transport; (f) several key proteins, including prophage P2b protein 18, CadA, mntA and lp_3327.
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Affiliation(s)
- Qixiao Zhai
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, People's Republic of China.,UK-China Joint Centre on Probiotic Bacteria, Norwich, NR4 7UA, UK
| | - Yue Xiao
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Fengwei Tian
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, People's Republic of China.,UK-China Joint Centre on Probiotic Bacteria, Norwich, NR4 7UA, UK
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, People's Republic of China.,UK-China Joint Centre on Probiotic Bacteria, Norwich, NR4 7UA, UK
| | - Arjan Narbad
- UK-China Joint Centre on Probiotic Bacteria, Norwich, NR4 7UA, UK.,Gut Health and Food Safety Programme, Institute of Food Research, Norwich, NR4 7UA, United Kingdom
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, People's Republic of China. .,UK-China Joint Centre on Probiotic Bacteria, Norwich, NR4 7UA, UK. .,Beijing Innovation Centre of Food Nutrition and Human Health, Beijing Technology & Business University, Beijing, 100048, People's Republic of China.
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Mumm K, Ainsaar K, Kasvandik S, Tenson T, Hõrak R. Responses of Pseudomonas putida to Zinc Excess Determined at the Proteome Level: Pathways Dependent and Independent of ColRS. J Proteome Res 2016; 15:4349-4368. [DOI: 10.1021/acs.jproteome.6b00420] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Karl Mumm
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
| | - Kadi Ainsaar
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
| | - Sergo Kasvandik
- Institute of Technology, University of Tartu, Tartu 50411, Estonia
| | - Tanel Tenson
- Institute of Technology, University of Tartu, Tartu 50411, Estonia
| | - Rita Hõrak
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
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58
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Li J, Wei X, Yu P, Deng X, Xu W, Ma M, Zhang H. Expression of cadR Enhances its Specific Activity for Cd Detoxification and Accumulation in Arabidopsis. PLANT & CELL PHYSIOLOGY 2016; 57:1720-1731. [PMID: 27382127 DOI: 10.1093/pcp/pcw093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 05/02/2016] [Indexed: 06/06/2023]
Abstract
Cadmium (Cd) is a transition metal that is highly toxic in biological systems. Anthropogenic emissions of Cd have increased biogeochemical cycling and the amount of Cd in the biosphere. Here we studied the utility of a bacterial Cd-binding protein, CadR, for the remediation of Cd contamination. CadR was successfully targeted to chloroplasts using a constitutive Cauliflower mosaic virus (CaMV) 35S promoter or a shoot-specific Chl a/b-binding protein 2 gene (CAB2) promoter and an RbcS (small subunit of the Rubisco complex) transit peptide. Under short-term (2 d) exposure to Cd, the cadR transgenic plants showed up to a 2.9-fold Cd accumulation in roots compared with untransformed plants. Under medium term (7 d) exposure to Cd, the concentrations of Cd in leaves began to increase but there were no differences between the wild type and the cadR transgenic plants. Under long-term (16 d) exposure to Cd, the cadR transgenic plants accumulated greater amounts of Cd in leaves than the untransformed plants. Total Cd accumulation (µg per plant) in shoots and roots of the plants expressing cadR were significantly higher (up to 3.5-fold in shoots and 5.2-fold in roots) than those of the untransformed plants. We also found that targeting CadR to chloroplasts facilitated chloroplastic metal homeostasis and Chl b accumulation. Our results demonstrate that manipulating chelating capacity in chloroplasts or in the cytoplasm may be effective in modifying both the accumulation of and resistance to Cd.
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Affiliation(s)
- Jingrui Li
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China College of Life Science, Shanxi Normal University, Shanxi Linfen 041004, China These authors contributed equally to this work
| | - Xuezhi Wei
- College of Life Science, Shanxi Normal University, Shanxi Linfen 041004, China These authors contributed equally to this work
| | - Pengli Yu
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xin Deng
- Department of Chemistry and Institute for Biophysical Dynamics, the University of Chicago, Chicago, IL 60637, USA
| | - Wenxiu Xu
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Mi Ma
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Haiyan Zhang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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Pishchik VN, Vorob’ev NI, Provorov NA, Khomyakov YV. Mechanisms of plant and microbial adaptation to heavy metals in plant–microbial systems. Microbiology (Reading) 2016. [DOI: 10.1134/s0026261716030097] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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60
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Icgen B, Yilmaz F. Use of cadA-Specific Primers and DNA Probes as Tools to Select Cadmium Biosorbents with Potential in Remediation Strategies. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2016; 96:685-693. [PMID: 26969609 DOI: 10.1007/s00128-016-1767-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 03/02/2016] [Indexed: 06/05/2023]
Abstract
Biosorption, using cadmium-resistant bacterial isolates, is often regarded as a relatively inexpensive and efficient way of cleaning up wastes, sediments, or soils polluted with cadmium. Therefore, many efforts have been devoted to the isolation of cadmium-resistant isolates for the efficient management of cadmium remediation processes. However, isolation, identification and in situ screening of efficient cadmium-resistant isolates are primary challenges. To overcome these challanges, in this study, cadA, cadmium resistance coding gene, specific primers and DNA probes were used to identify and screen cadmium-resistant bacteria in the cadmium-polluted river waters through polymerase chain reaction (PCR) and fluorescein in situ hybridization (FISH). PCR amplification of the cadA amplicon coupled with 16S rRNA sequencing revealed various gram-positive and -negative bacterial isolates harboring cadA. Accordingly, a cadA-mediated DNA probe was prepared and used for in situ screening of cadmium-resistant isolates from water samples collected from cadmium-polluted river waters. The FISH analyses of cadA probe showed highly specific and efficient hybridization with cadA harboring isolates. The use of primers and DNA probes specific for cadA gene seems to be very helpful tools for the selection and screening of cadmium biosorbents with potential to be used in the remediation of cadmium-polluted sites.
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Affiliation(s)
- Bulent Icgen
- Department of Environmental Engineering, Middle East Technical University, 06800, Ankara, Turkey.
| | - Fadime Yilmaz
- Department of Environmental Engineering, Middle East Technical University, 06800, Ankara, Turkey
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61
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Wu W, Huang H, Ling Z, Yu Z, Jiang Y, Liu P, Li X. Genome sequencing reveals mechanisms for heavy metal resistance and polycyclic aromatic hydrocarbon degradation in Delftia lacustris strain LZ-C. ECOTOXICOLOGY (LONDON, ENGLAND) 2016; 25:234-247. [PMID: 26589947 DOI: 10.1007/s10646-015-1583-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/30/2015] [Indexed: 06/05/2023]
Abstract
Strain LZ-C, isolated from a petrochemical wastewater discharge site, was found to be resistant to heavy metals and to degrade various aromatic compounds, including naphenol, naphthalene, 2-methylnaphthalene and toluene. Data obtained from 16S rRNA gene sequencing showed that this strain was closely related to Delftia lacustris. The 5,889,360 bp genome of strain LZ-C was assembled into 239 contigs and 197 scaffolds containing 5855 predicted open reading frames (ORFs). Among these predicted ORFs, 464 were different from the type strain of Delftia. The minimal inhibitory concentrations were 4 mM, 30 µM, 2 mM and 1 mM for Cr(VI), Hg(II), Cd(II) and Pb(II), respectively. Both genome sequencing and quantitative real-time PCR data revealed that genes related to Chr, Czc and Mer family genes play important roles in heavy metal resistance in strain LZ-C. In addition, the Na(+)/H(+) antiporter NhaA is important for adaptation to high salinity resistance (2.5 M NaCl). The complete pathways of benzene and benzoate degradation were identified through KEGG analysis. Interestingly, strain LZ-C also degrades naphthalene but lacks the key naphthalene degradation gene NahA. Thus, we propose that strain LZ-C exhibits a novel protein with a function similar to NahA. This study is the first to reveal the mechanisms of heavy metal resistance and salinity tolerance in D. lacustris and to identify a potential 2-methylnaphthalene degradation protein in this strain. Through whole-genome sequencing analysis, strain LZ-C might be a good candidate for the bioremediation of heavy metals and polycyclic aromatic hydrocarbons.
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Affiliation(s)
- Wenyang Wu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China
| | - Haiying Huang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China
| | - Zhenmin Ling
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China
| | - Zhengsheng Yu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China
| | - Yiming Jiang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China
| | - Pu Liu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China
| | - Xiangkai Li
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China.
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Moulis JM, Bourguignon J, Catty P. Cadmium. BINDING, TRANSPORT AND STORAGE OF METAL IONS IN BIOLOGICAL CELLS 2014. [DOI: 10.1039/9781849739979-00695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cadmium is not an essential element for life. It is geologically marginal but anthropogenic activities have contributed significantly to its dispersion in the environment and to cadmium exposure of living species. The natural speciation of the divalent cation Cd2+ is dominated by its high propensity to bind to sulfur ligands, but Cd2+ may also occupy sites providing imidazole and carboxylate ligands. It binds to cell walls by passive adsorption (bio-sorption) and it may interact with surface receptors. Cellular uptake can occur by ion mimicry through a variety of transporters of essential divalent cations, but not always. Once inside cells, Cd2+ preferentially binds to thiol-rich molecules. It can accumulate in intracellular vesicles. It may also be transported over long distances within multicellular organisms and be trapped in locations devoid of efficient excretion systems. These locations include the renal cortex of animals and the leaves of hyper-accumulating plants. No specific regulatory mechanism monitors Cd2+ cellular concentrations. Thiol recruitment by cadmium is a major interference mechanism with many signalling pathways that rely on thiolate-disulfide equilibria and other redox-related processes. Cadmium thus compromises the antioxidant intracellular response that relies heavily on molecules with reactive thiolates. These biochemical features dominate cadmium toxicity, which is complex because of the diversity of the biological targets and the consequent pleiotropic effects. This chapter compares the cadmium-handling systems known throughout phylogeny and highlights the basic principles underlying the impact of cadmium in biology.
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Affiliation(s)
- Jean-Marc Moulis
- CEA, Institut de Recherches en Technologies et Sciences pour le Vivant, Laboratoire Chimie et Biologie des Métaux 17 rue des Martyrs F-38054 Grenoble France
- CNRS UMR5249 F-38054 Grenoble France
- Université Joseph Fourier-Grenoble I UMR5249 F-38041 Grenoble France
| | - Jacques Bourguignon
- CEA, Institut de Recherches en Technologies et Sciences pour le Vivant, Laboratoire Physiologie Cellulaire et Végétale F-38054 Grenoble France
- CNRS UMR5168 F-38054 Grenoble France
- Université Joseph Fourier-Grenoble I UMR5168 F-38041 Grenoble France
- INRA USC1359 F-38054 Grenoble France
| | - Patrice Catty
- CEA, Institut de Recherches en Technologies et Sciences pour le Vivant, Laboratoire Chimie et Biologie des Métaux 17 rue des Martyrs F-38054 Grenoble France
- CNRS UMR5249 F-38054 Grenoble France
- Université Joseph Fourier-Grenoble I UMR5249 F-38041 Grenoble France
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63
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Hynninen A, Virta M. Whole-cell bioreporters for the detection of bioavailable metals. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 118:31-63. [PMID: 19543702 DOI: 10.1007/10_2009_9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
Whole-cell bioreporters are living microorganisms that produce a specific, quantifiable output in response to target chemicals. Typically, whole-cell bioreporters combine a sensor element for the substance of interest and a reporter element coding for an easily detectable protein. The sensor element is responsible for recognizing the presence of an analyte. In the case of metal bioreporters, the sensor element consists of a DNA promoter region for a metal-binding transcription factor fused to a promoterless reporter gene that encodes a signal-producing protein. In this review, we provide an overview of specific whole-cell bioreporters for heavy metals. Because the sensing of metals by bioreporter microorganisms is usually based on heavy metal resistance/homeostasis mechanisms, the basis of these mechanisms will also be discussed. The goal here is not to present a comprehensive summary of individual metal-specific bioreporters that have been constructed, but rather to express views on the theory and applications of metal-specific bioreporters and identify some directions for future research and development.
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Affiliation(s)
- Anu Hynninen
- Department of Applied Chemistry and Microbiology, University of Helsinki, 56, 00014, Helsinki, Finland
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Molecular and in situ characterization of cadmium-resistant diversified extremophilic strains of Pseudomonas for their bioremediation potential. 3 Biotech 2014; 4:297-304. [PMID: 28324433 PMCID: PMC4026450 DOI: 10.1007/s13205-013-0155-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 07/08/2013] [Indexed: 11/29/2022] Open
Abstract
Cadmium-resistant strains psychrotolerant Pseudomonas putida SB32 and alkalophilic Pseudomonas monteilli SB35 were originally isolated from the soil of Semera mines, Palamau, Jharkhand, India. Further, to unravel the mechanism involved in cadmium resistance, plasmid DNA was isolated from the strains and subjected to amplification of the czc gene, which is responsible for the efflux of three metal cations, viz. Co, Zn and Cd, from the cell. Furthermore, the amplicon was cloned into pDrive cloning vector and sequenced. When compared with the available database, the sequence homology of the cloned gene showed the presence of a partial czcA gene sequence, thereby indicating the presence of a plasmid-mediated efflux mechanism for resistance in both strains. These results were further confirmed by atomic absorption spectroscopy and transmission electron microscopy. Moreover, the strains were characterized functionally for their bioremediation potential in cadmium-contaminated soil by performing an in situ experiment using soybean plant. A marked increase in agronomical parameters was observed in presence of both strains. Further, the concentration of metal ions decreased in both plants and soil in the presence of these bioinoculants.
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65
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Kobayashi K, Fujikawa M, Kozawa T. Oxidative stress sensing by the iron-sulfur cluster in the transcription factor, SoxR. J Inorg Biochem 2013; 133:87-91. [PMID: 24332474 DOI: 10.1016/j.jinorgbio.2013.11.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 11/20/2013] [Accepted: 11/21/2013] [Indexed: 11/28/2022]
Abstract
All bacteria are continuously exposed to environmental and/or endogenously active oxygen and nitrogen compounds and radicals. To reduce the deleterious effects of these reactive species, most bacteria have evolved specific sensor proteins that regulate the expression of enzymes that detoxify these species and repair proteins. Some bacterial transcriptional regulators containing an iron-sulfur cluster are involved in coordinating these physiological responses. Mechanistic and structural information can show how these regulators function, in particular, how chemical interactions at the cluster drive subsequent regulatory responses. The [2Fe-2S] transcription factor SoxR (superoxide response) functions as a bacterial sensor of oxidative stress and nitric oxide (NO). This review focuses on the mechanisms by which SoxR proteins respond to oxidative stress.
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Affiliation(s)
- Kazuo Kobayashi
- The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
| | - Mayu Fujikawa
- The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Takahiro Kozawa
- The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Hložková K, Suman J, Strnad H, Ruml T, Paces V, Kotrba P. Characterization of pbt genes conferring increased Pb2+ and Cd2+ tolerance upon Achromobacter xylosoxidans A8. Res Microbiol 2013; 164:1009-18. [PMID: 24125695 DOI: 10.1016/j.resmic.2013.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 09/03/2013] [Indexed: 10/26/2022]
Abstract
The cluster of pbtTFYRABC genes is carried by plasmid pA81. Its elimination from Achromobacter xylosoxidans A8 resulted in increased sensitivity towards Pb(2+) and Cd(2+). Predicted pbtTRABC products share strong similarities with Pb(2+) uptake transporter PbrT, transcriptional regulator PbrR, metal efflux P1-ATPases PbrA and CadA, undecaprenyl pyrophosphatase PbrB and its signal peptidase PbrC from Cupriavidus metallidurans CH34. Expression of pbtABC or pbtA in a metal-sensitive Escherichia coli GG48 rendered the strain Pb(2+)-, Cd(2+)- and Zn(2+)-tolerant and caused decreased accumulation of the metal ions. Accumulation of Pb(2+), but not of Cd(2+) or Zn(2+), was promoted in E. coli expressing pbtT. Additional genes of the pbt cluster are pbtF and pbtY, which encode the cation diffusion facilitator (CDF)-like transporter and a putative fatty acid hydroxylase of unknown function, respectively. Expression of pbtF did not confer increased metal tolerance upon E. coli GG48, although the protein showed measurable Pb(2+)-efflux activity. Unlike the pbtT promoter, promoters of pbtABC, pbtF and pbtY contain features characteristic of promoters controlled by metal-responsive transcriptional regulators of the MerR family. Upregulation of pbtABC, pbtF and pbtY upon Pb(2+), Cd(2+) and Zn(2+) exposure was confirmed in wild-type Achromobacter xylosoxidans A8. Gel shift assays proved binding of purified PbtR to the respective promoters.
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Affiliation(s)
- Kateřina Hložková
- Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Technická 3, CZ-166 28 Prague, Czech Republic.
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67
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Wasi S, Tabrez S, Ahmad M. Use of Pseudomonas spp. for the bioremediation of environmental pollutants: a review. ENVIRONMENTAL MONITORING AND ASSESSMENT 2013; 185:8147-55. [PMID: 23519843 DOI: 10.1007/s10661-013-3163-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 03/04/2013] [Indexed: 05/27/2023]
Abstract
Environmental pollution implies any alteration in the surroundings but it is restricted in use especially to mean any deterioration in the physical, chemical, and biological quality of the environment. All types of pollution, directly or indirectly, affect human health. Present scenario of pollution calls for immediate attention towards the remediation and detoxification of these hazardous agents in order to have a healthy living environment. The present communication will deal with the use of naturally occurring microbes capable of bioremediating the major environmental pollutants.
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Affiliation(s)
- Samina Wasi
- College of Medicine, University of Dammam, P.O. Box 2114, Dammam, 31451, Saudi Arabia.
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68
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Shamim S, Rehman A. Antioxidative enzyme profiling and biosorption ability of Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 under cadmium stress. J Basic Microbiol 2013; 55:374-81. [PMID: 23832807 DOI: 10.1002/jobm.201300038] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 05/09/2013] [Indexed: 11/09/2022]
Abstract
Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 were used as cadmium (Cd)-resistant and -sensitive bacteria, respectively, to study their biosorption ability and their antioxidative enzymes. The minimal inhibitory concentration of C. metallidurans CH34 for Cd was found to be 30 mM, and for P. putida mt2 it was 1.25 mM. The tube dilution method revealed the heavy-metal resistance pattern of C. metallidurans CH34 as Ni(2+) (10 mM)>Zn(2+) (4 mM)>Cu(2+) (2 mM)>Hg(2+) (1 mM)>Cr(2+) (1 mM)>Pb(2+) (0 mM), whereas P. putida mt2 was only resistant to Zn(2+) (1 mM). Under Cd stress, the induction of GSH was higher in C. metallidurans CH34 (0.359 ± 0.010 mM g(-1) FW) than in P. putida mt2 (0.286 ± 0.005 mM g(-1) FW). Glutathione reductase was more highly expressed in the mt2 strain, in contrast to non-protein thiols and peroxidase. Unlike dead bacterial cells, live cells of both bacteria showed significant Cd biosorption, i.e. more than 80% at 48 h. C. metallidurans CH34 used only catalase, whereas P. putida mt2 used superoxide dismutase and ascorbate peroxidase to combat Cd stress. This study investigated the Cd biosorption ability and enzymes involved in the Cd detoxification mechanisms of C. metallidurans CH34 and P. putida mt2.
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Affiliation(s)
- Saba Shamim
- Department of Microbiology and Molecular Genetics, University of the Punjab, New Campus, Lahore, Pakistan; Department of Environmental Microbiology-UMB, Helmholtz Center for Environmental Research-UFZ, Leipzig, Germany
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69
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Live-cell dynamic sensing of Cd(2+) with a FRET-based indicator. PLoS One 2013; 8:e65853. [PMID: 23776557 PMCID: PMC3679114 DOI: 10.1371/journal.pone.0065853] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 05/03/2013] [Indexed: 11/19/2022] Open
Abstract
Cd2+ causes damages to several human tissues. Although the toxicological and carcinogenetic mechanisms of Cd2+ have been previously established, some basic questions on this toxicant remain unclear. In this study, we constructed Met-cad 1.57, a new fluorescent resonance energy transfer (FRET)-based Cd2+ indicator, which contains a portion of a Cd2+-binding protein (CadR) obtained from Pseudomonas putida as the Cd2+ sensing key. We produced a human embryonic kidney cell line HEK-MCD157 which stably expresses the Met-cad 1.57 for further investigations. Both fluorescence spectroscopy and FRET microscopic ratio imaging were used to monitor the Cd2+ concentration within the living HEK-MCD157 cells. The dissociation constant of Met-cad 1.57 was approximately 271 nM. The function of Ca2+ channels as a potential Cd2+ entry gateway was further confirmed in the HEK-MCD157 cells. The organelle-targeted property of the protein-based Cd2+ indicator directly reveals the nucleus accumulation phenomena. In summary, a human kidney cell line that stably expresses the FRET-based Cd2+ indicator Met-cad 1.57 was constructed for reliable and convenient investigations to determine the Cd2+ concentration within living cells, including the identification of the entry pathway of Cd2+ and sub-cellular sequestration.
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70
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Checa SK, Zurbriggen MD, Soncini FC. Bacterial signaling systems as platforms for rational design of new generations of biosensors. Curr Opin Biotechnol 2012; 23:766-72. [DOI: 10.1016/j.copbio.2012.05.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 05/08/2012] [Accepted: 05/09/2012] [Indexed: 01/30/2023]
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71
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Hobman JL, Julian DJ, Brown NL. Cysteine coordination of Pb(II) is involved in the PbrR-dependent activation of the lead-resistance promoter, PpbrA, from Cupriavidus metallidurans CH34. BMC Microbiol 2012; 12:109. [PMID: 22708803 PMCID: PMC3431237 DOI: 10.1186/1471-2180-12-109] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Accepted: 06/07/2012] [Indexed: 11/30/2022] Open
Abstract
Background The pbr resistance operon from Cupriavidus metallidurans CH34 plasmid pMOL30 confers resistance to Pb(II) salts, and is regulated by the Pb(II) responsive regulator PbrR, which is a MerR family activator. In other metal sensing MerR family regulators, such as MerR, CueR, and ZntR the cognate regulator binds to a promoter with an unusually long spacer between the −35 and −10 sequences, and activates transcription of resistance genes as a consequence of binding the appropriate metal. Cysteine residues in these regulators are essential for metal ion coordination and activation of expression from their cognate promoter. In this study we investigated the interaction of PbrR with the promoter for the structural pbr resistance genes, PpbrA, effects on transcriptional activation of altering the DNA sequence of PpbrA, and effects on Pb(II)-induced activation of PpbrA when cysteine residues in PbrR were mutated to serine. Results Gel retardation and footprinting assays using purified PbrR show that it binds to, and protects from DNase I digestion, the PpbrA promoter, which has a 19 bp spacer between its −35 and −10 sites. Using β-galactosidase assays in C. metallidurans, we show that when PpbrA is changed to an 18 bp spacer, there is an increase in transcriptional activation both in the presence and absence of Pb(II) salts up to a maximum induction equivalent to that seen in the fully-induced wild-type promoter. Changes to the −10 sequence of PpbrA from TTAAAT to the consensus E. coli −10 sequence (TATAAT) increased transcriptional activation from PpbrA, whilst changing the −10 sequence to that of the Tn501 mer promoter (TAAGGT) also increased the transcriptional response, but only in the presence of Pb(II). Individual PbrR mutants C14S, C55S, C79S, C114S, C123S, C132S and C134S, and a double mutant C132S/C134S, were tested for Pb(II) response from PpbrA, using β-galactosidase assays in C. metallidurans. The PbrR C14S, C79S, C134S, and C132S/C134S mutants were defective in Pb(II)-induced activation of PpbrA. Conclusions These data show that the metal-dependent activation of PbrR occurs by a similar mechanism to that of MerR, but that metal ion coordination is through cysteines which differ from those seen in other MerR family regulators, and that the DNA sequence of the −10 promoter affects expression levels of the lead resistance genes.
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Affiliation(s)
- Jon L Hobman
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK.
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72
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Deletion of TnAbaR23 results in both expected and unexpected antibiogram changes in a multidrug-resistant Acinetobacter baumannii strain. Antimicrob Agents Chemother 2012; 56:1845-53. [PMID: 22290963 DOI: 10.1128/aac.05334-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Since the 2006 discovery of the Acinetobacter baumannii strain AYE AbaR1 resistance island, similar elements have been reported in numerous members of this species. As AbaR1 is distantly related to Tn7, we have renamed it TnAbaR1. TnAbaR transposons are known to carry multiple antibiotic resistance- and efflux-associated genes, although none have been experimentally studied en bloc. We deleted the TnAbaR transposon in A. baumannii A424, which we have designated TnAbaR23, and characterized independent deletion mutants DCO163 and DCO174. The NotI pulsed-field gel electrophoresis (PFGE) profile of strain DCO174 was consistent with targeted deletion of TnAbaR23 alone, but strain DCO163 apparently harbored a second large genomic deletion. Nevertheless, "subtractive amplification" targeting 52 TnAbaR and/or resistance-associated loci yielded identical results for both mutants and highlighted genes lost relative to strain A424. PCR mapping and genome sequencing revealed the entire 48.3-kb sequence of TnAbaR23. Consistent with TnAbaR23 carrying two copies of sul1, both mutants exhibited markedly increased susceptibility to sulfamethoxazole. In contrast, loss of tetAR(A) resulted in only a minor and variable increase in tetracycline susceptibility. Despite not exhibiting a growth handicap, strain DCO163 was more susceptible than strain DCO174 to 9 of 10 antibiotics associated with mutant-to-mutant variation in susceptibility, suggesting impairment of an undefined resistance-associated function. Remarkably, despite all three strains sharing identical gyrA and parC sequences, the ciprofloxacin MIC of DCO174 was >8-fold that of DCO163 and A424, suggesting a possible paradoxical role for TnAbaR23 in promoting sensitivity to ciprofloxacin. This study highlights the importance of experimental scrutiny and challenges the assumption that resistance phenotypes can reliably be predicted from genotypes alone.
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73
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Kobayashi K, Mizuno M, Fujikawa M, Mizutani Y. Protein conformational changes of the oxidative stress sensor, SoxR, upon redox changes of the [2Fe-2S] cluster probed with ultraviolet resonance Raman spectroscopy. Biochemistry 2011; 50:9468-74. [PMID: 21988663 DOI: 10.1021/bi201526y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The [2Fe-2S] transcription factor, SoxR, a member of the MerR family, functions as a bacterial sensor of oxidative stress in Escherichia coli. SoxR is activated by reversible one-electron oxidation of the [2Fe-2S] cluster and enhances the production of various antioxidant proteins through the SoxRS regulon. Ultraviolet resonance Raman (UVRR) spectroscopic analysis of SoxR revealed conformational changes upon reduction of the [2Fe-2S] cluster in the absence and presence of promoter oligonucleotide. UVRR spectra reflected the environmental or structural changes of Trp following reduction. Notably, the environment around Trp91 contacting the [2Fe-2S] cluster was altered to become more hydrophilic, whereas that around Trp98 exhibited a small change to become more hydrophobic. In addition, changes in cation-π interactions between the [2Fe-2S] cluster and Trp91 were suggested. On the other hand, the environment around Tyr was barely affected by the [2Fe-2S] reduction. Binding of the promoter oligonucleotide triggered changes in Tyr located in the DNA-binding domain, but not Trp. Furthermore, conformational changes induced upon reduction of DNA-bound SoxR were not significantly different from those of DNA-free SoxR.
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Affiliation(s)
- Kazuo Kobayashi
- The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
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74
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Raja CE, Selvam GS. Characterization of chromosomal mediated cadmium resistance inPseudomonas aeruginosastrain BC15. J Basic Microbiol 2011; 52:175-83. [DOI: 10.1002/jobm.201000408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 05/01/2011] [Indexed: 11/11/2022]
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75
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Cd-specific mutants of mercury-sensing regulatory protein MerR, generated by directed evolution. Appl Environ Microbiol 2011; 77:6215-24. [PMID: 21764963 DOI: 10.1128/aem.00662-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mercury-sensing regulatory protein, MerR (Tn21), which regulates mercury resistance operons in Gram-negative bacteria, was subjected to directed evolution in an effort to generate a MerR mutant that responds to Cd but not Hg. Oligonucleotide-directed mutagenesis was used to introduce random mutations into the key metal-binding regions of MerR. The effects of these mutations were assessed using a vector in which MerR controlled the expression of green fluorescent protein (GFP) and luciferase via the mer operator/promoter. An Escherichia coli cell library was screened by fluorescence-activated cell sorting, using a fluorescence-based dual screening strategy that selected for MerR mutants that showed GFP repression when cells were induced with Hg but GFP activation in the presence of Cd. Two Cd-responsive MerR mutants with decreased responses toward Hg were identified through the first mutagenesis/selection round. These mutants were used for a second mutagenesis/selection round, which yielded eight Cd-specific mutants that had no significant response to Hg, Zn, or the other tested metal(loid)s. Seven of the eight Cd-specific MerR mutants showed repressor activities equal to that of wild-type (wt) MerR. These Cd-specific mutants harbored multiple mutations (12 to 22) in MerR, indicating that the alteration of metal specificity with maintenance of repressor function was due to the combined effect of many mutations rather than just a few amino acid changes. The amino acid changes were studied by alignment against the sequences of MerR and other metal-responsive MerR family proteins. The analysis indicated that the generated Cd-specific MerR mutants appear to be unique among the MerR family members characterized to date.
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76
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Singh JS, Abhilash P, Singh H, Singh RP, Singh D. Genetically engineered bacteria: An emerging tool for environmental remediation and future research perspectives. Gene 2011; 480:1-9. [DOI: 10.1016/j.gene.2011.03.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 02/25/2011] [Accepted: 03/03/2011] [Indexed: 10/18/2022]
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77
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Hynninen A, Tönismann K, Virta M. Improving the sensitivity of bacterial bioreporters for heavy metals. Bioeng Bugs 2009; 1:132-8. [PMID: 21326938 DOI: 10.4161/bbug.1.2.10902] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 11/30/2009] [Accepted: 12/02/2009] [Indexed: 11/19/2022] Open
Abstract
Whole-cell bacterial bioreporters represent a convenient testing method for quantifying the bioavailability of contaminants in environmental samples. Despite the fact that several bioreporters have been constructed for measuring heavy metals, their application to environmental samples has remained minimal. The major drawbacks of the available bioreporters include a lack of sensitivity and specificity. Here, we report an improvement in the limit of detection of bacterial bioreporters by interfering with the natural metal homeostasis system of the host bacterium. The limit of detection of a Pseudomonas putida KT2440-based Zn/Cd/Pb-biosensor was improved by a factor of up to 45 by disrupting four main efflux transporters for Zn/Cd/Pb and thereby causing the metals to accumulate in the cell. The specificity of the bioreporter could be modified by changing the sensor element. A Zn-specific bioreporter was achieved by using the promoter of the cadA1 gene from P. putida as a sensor element. The constructed transporter-deficient P. putida reporter strain detected Zn(2+) concentrations about 50 times lower than that possible with other available Zn-bioreporters. The achieved detection limits were significantly below the permitted limit values for Zn and Pb in water and in soil, allowing for reliable detection of heavy metals in the environment.
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Affiliation(s)
- Anu Hynninen
- Department of Applied Chemistry and Microbiology, University of Helsinki, Helsinki, Finland.
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78
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Ma Z, Jacobsen FE, Giedroc DP. Coordination chemistry of bacterial metal transport and sensing. Chem Rev 2009; 109:4644-81. [PMID: 19788177 PMCID: PMC2783614 DOI: 10.1021/cr900077w] [Citation(s) in RCA: 426] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Zhen Ma
- Department of Chemistry, Indiana University, Bloomington, IN 47401-7005 USA
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128 USA
| | - Faith E. Jacobsen
- Department of Chemistry, Indiana University, Bloomington, IN 47401-7005 USA
| | - David P. Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47401-7005 USA
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79
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Wu CH, Le D, Mulchandani A, Chen W. Optimization of a whole-cell cadmium sensor with a toggle gene circuit. Biotechnol Prog 2009; 25:898-903. [PMID: 19507257 DOI: 10.1002/btpr.203] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This work demonstrates improvement of a whole-cell cadmium detection sensor through construction of a gene circuit. A cadmium (II) specific regulatory promoter, P(cadR,) from Psuedomonas putida 06909, is used in the assembly of a toggle circuit. The circuit contains the cadR promoter fused to lacIq and gfp, and a divergently transcribed tac promoter and cadR. The toggle sensor exhibits lower background fluorescence, and a 20-fold lower detection limit in comparison to a nontoggle gene circuit. The detection limit of the toggle sensor is 0.01 microM (1.12 ppb) cadmium chloride, and tunable with the addition of isopropyl-b-D-thiogalactopyranoside (IPTG). The toggle sensor is highly specific to cadmium (II), and no response is elicited from zinc, lead, manganese, nickel, copper, and mercury.
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Affiliation(s)
- Cindy H Wu
- Dept. of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA
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80
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MrdH, a novel metal resistance determinant of Pseudomonas putida KT2440, is flanked by metal-inducible mobile genetic elements. J Bacteriol 2009; 191:5976-87. [PMID: 19648243 DOI: 10.1128/jb.00465-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We report here the identification and characterization of mrdH, a novel chromosomal metal resistance determinant, located in the genomic island 55 of Pseudomonas putida KT2440. It encodes for MrdH, a predicted protein of approximately 40 kDa with a chimeric domain organization derived from the RcnA and RND (for resistance-nodulation-cell division) metal efflux proteins. The metal resistance function of mrdH was identified by the ability to confer nickel resistance upon its complementation into rcnA mutant (a nickel- and cobalt-sensitive mutant) of Escherichia coli. However, the disruption of mrdH in P. putida resulted in an increased sensitivity to cadmium and zinc apart from nickel. Expression studies using quantitative reverse transcription-PCR showed the induction of mrdH by cadmium, nickel, zinc, and cobalt. In association with mrdH, we also identified a conserved hypothetical gene mreA whose encoded protein showed significant homology to NreA and NreA-like proteins. Expression of the mreA gene in rcnA mutant of E. coli enhanced its cadmium and nickel resistance. Transcriptional studies showed that both mrdH and mreA underwent parallel changes in gene expression. The mobile genetic elements Tn4652 and IS1246, flanking mrdH and mreA were found to be induced by cadmium, nickel, and zinc, but not by cobalt. This study is the first report of a single-component metal efflux transporter, mrdH, showing chimeric domain organization, a broad substrate spectrum, and a location amid metal-inducible mobile genetic elements.
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81
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Ali N, Hameed A, Ahmed S. Physicochemical characterization and Bioremediation perspective of textile effluent, dyes and metals by indigenous Bacteria. JOURNAL OF HAZARDOUS MATERIALS 2009; 164:322-328. [PMID: 18818017 DOI: 10.1016/j.jhazmat.2008.08.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 07/04/2008] [Accepted: 08/06/2008] [Indexed: 05/26/2023]
Abstract
Physicochemical and bacteriological status of a local textile mill effluent showed considerably high values of temperature (40 degrees C), pH (9.50), EC (3.57mus/m), BOD (548mgl(-1)), COD (1632mgl(-1)), TSS (5496mgl(-1)), TDS (2512mgl(-1)), heavy metals ions (0.28-6.36mgl(-1)) and color above the prescribed fresh water limits. However, a considerable decline in almost all pollution indicators from source to sink indicated signs of natural remediation. Ten bacteria strains isolated from effluent showed comparatively higher resistance (MRL) (mgl(-1)) (average) for 10 heavy metals than against four structurally different dyes tested on solid media of mineral salt. Overall bacterial resistance was quite high against Fe(3+) (2820), Cr(3+) (1203), Zn(2+) (1122), Mn(2+) (804) and Pb(2+) (435), whereas, it varied amid 300-500 in four dyes. Bacterial decolorization/degradation of dyes indicated on solid media was confirmed through experiments carried out in liquid broth.
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Affiliation(s)
- Naeem Ali
- Department of Environmental Sciences, Faculty of Basic and Applied Science, International Islamic University, Islamabad, Pakistan.
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82
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Ivask A, Rõlova T, Kahru A. A suite of recombinant luminescent bacterial strains for the quantification of bioavailable heavy metals and toxicity testing. BMC Biotechnol 2009; 9:41. [PMID: 19426479 PMCID: PMC2685376 DOI: 10.1186/1472-6750-9-41] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 05/08/2009] [Indexed: 02/01/2023] Open
Abstract
Background Recombinant whole-cell sensors have already proven useful in the assessment of the bioavailability of environmental pollutants like heavy metals and organic compounds. In this work 19 recombinant bacterial strains representing various Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas fluorescens) bacteria were constructed to express the luminescence encoding genes luxCDABE (from Photorhabdus luminescens) as a response to bioavailable heavy metals ("lights-on" metal sensors containing metal-response elements, 13 strains) or in a constitutive manner ("lights-off" constructs, 6 strains). Results The bioluminescence of all 13 "lights-on" metal sensor strains was expressed as a function of the sub-toxic metal concentrations enabling the quantitative determination of metals bioavailable for these strains. Five sensor strains, constructed for detecting copper and mercury, proved to be target metal specific, whereas eight other sensor strains were simultaneously induced by Cd2+, Hg2+, Zn2+and Pb2+. The lowest limits of determination of the "lights-on" sensor strains for the metals tested in this study were (μg l-1): 0.002 of CH3HgCl, 0.03 of HgCl2, 1.8 of CdCl2, 33 of Pb(NO3)2, 1626 of ZnSO4, 24 of CuSO4 and 340 of AgNO3. In general, the sensitivity of the "lights-on" sensor strains was mostly dependent on the metal-response element used while the selection of host bacterium played a relatively minor role. In contrast, toxicity of metals to the "lights-off" strains was only dependent on the bacterial host so that Gram-positive strains were remarkably more sensitive than Gram-negative ones. Conclusion The constructed battery of 19 recombinant luminescent bacterial strains exhibits several novel aspects as it contains i) metal sensor strains with similar metal-response elements in different host bacteria; ii) metal sensor strains with metal-response elements in different copies and iii) a "lights-off" construct (control) for every constructed recombinant metal sensor strain. To our knowledge, no Gram-positive metal sensor expressing a full bacterial bioluminescence cassette (luxCDABE) has been constructed previously.
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Affiliation(s)
- Angela Ivask
- Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn, Estonia.
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83
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Summers AO. Damage control: regulating defenses against toxic metals and metalloids. Curr Opin Microbiol 2009; 12:138-44. [PMID: 19282236 DOI: 10.1016/j.mib.2009.02.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2009] [Revised: 02/10/2009] [Accepted: 02/10/2009] [Indexed: 11/16/2022]
Abstract
Some elements are essential for life and others closely related to them are very toxic. In exploiting unique ecological niches many prokaryotes have evolved the means to defend themselves against and even to derive energy from deleterious elements. Toxic metal defense systems are related to those providing homeostasis of essential metals and metalloid elements. Expression of these multiprotein systems is costly but they must respond rapidly and, so, all are well controlled. Seven diverse families of metalloregulators are presently recognized for essential metal homeostasis in prokaryotes. Two of these, the ArsR and MerR families, figure more often than the others in controlling responses to toxic transition metals and metalloids. This review emphasizes recent advances in these two metalloregulator families and highlights emerging regulatory motifs of other types.
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Affiliation(s)
- Anne O Summers
- Department of Microbiology, The University of Georgia, Athens, 30602-2605, USA.
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84
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Kobayashi DY, Crouch JA. Bacterial/Fungal interactions: from pathogens to mutualistic endosymbionts. ANNUAL REVIEW OF PHYTOPATHOLOGY 2009; 47:63-82. [PMID: 19400650 DOI: 10.1146/annurev-phyto-080508-081729] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A fundamental issue in biology is the question of how bacteria initiate and maintain pathogenic relationships with eukaryotic hosts. Despite billions of years of coexistence, far less is known about bacterial/fungal interactions than the equivalent associations formed by either of these types of microorganisms with higher eukaryotes. This review highlights recent research advances in the field of bacterial/fungal interactions, and provides examples of the various forms such interactions may assume, ranging from simple antagonism and parasitism to more intimate associations of pathogenesis and endosymbiosis. Information derived from the associations of bacteria and fungi in the context of natural and agronomic ecosystems is emphasized, including interactions observed from biological control systems, endosymbiotic relationships, diseases of cultivated mushrooms, and model systems that expand our understanding of human disease. The benefits of studying these systems at the molecular level are also emphasized.
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Affiliation(s)
- Donald Y Kobayashi
- Department of Plant Biology & Pathology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901-8520, USA.
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85
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De J, Ramaiah N, Vardanyan L. Detoxification of toxic heavy metals by marine bacteria highly resistant to mercury. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2008; 10:471-7. [PMID: 18288535 DOI: 10.1007/s10126-008-9083-z] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 01/09/2008] [Indexed: 05/17/2023]
Abstract
Pollution in industrial areas is a serious environmental concern, and interest in bacterial resistance to heavy metals is of practical significance. Mercury (Hg), Cadmium (Cd), and lead (Pb) are known to cause damage to living organisms, including human beings. Several marine bacteria highly resistant to mercury (BHRM) capable of growing at 25 ppm (mg L(-1)) or higher concentrations of mercury were tested during this study to evaluate their potential to detoxify Cd and Pb. Results indicate their potential of detoxification not only of Hg, but also Cd and Pb. Through biochemical and 16S rRNA gene sequence analyses, these bacteria were identified to belong to Alcaligenes faecalis (seven isolates), Bacillus pumilus (three isolates), Bacillus sp. (one isolate), Pseudomonas aeruginosa (one isolate), and Brevibacterium iodinium (one isolate). The mechanisms of heavy metal detoxification were through volatilization (for Hg), putative entrapment in the extracellular polymeric substance (for Hg, Cd and Pb) as revealed by the scanning electron microscopy and energy dispersive x-ray spectroscopy, and/or precipitation as sulfide (for Pb). These bacteria removed more than 70% of Cd and 98% of Pb within 72 and 96 h, respectively, from growth medium that had initial metal concentrations of 100 ppm. Their detoxification efficiency for Hg, Cd and Pb indicates good potential for application in bioremediation of toxic heavy metals.
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Affiliation(s)
- Jaysankar De
- National Institute of Oceanography, Dona Paula, Goa, India.
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86
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Wu CH, Hwang YC, Lee W, Mulchandani A, Wood TK, Yates MV, Chen W. Detection of recombinant Pseudomonas putida in the wheat rhizosphere by fluorescence in situ hybridization targeting mRNA and rRNA. Appl Microbiol Biotechnol 2008; 79:511-8. [DOI: 10.1007/s00253-008-1438-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 02/21/2008] [Accepted: 02/29/2008] [Indexed: 11/30/2022]
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Klockgether J, Würdemann D, Wiehlmann L, Tümmler B. Transcript profiling of the Pseudomonas aeruginosa genomic islands PAGI-2 and pKLC102. Microbiology (Reading) 2008; 154:1599-1604. [DOI: 10.1099/mic.0.2007/014340-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Jens Klockgether
- Klinische Forschergruppe, OE 6710, Medizinische Hochschule Hannover, D-30625 Hannover, Germany
| | - Dieco Würdemann
- Klinische Forschergruppe, OE 6710, Medizinische Hochschule Hannover, D-30625 Hannover, Germany
| | - Lutz Wiehlmann
- Klinische Forschergruppe, OE 6710, Medizinische Hochschule Hannover, D-30625 Hannover, Germany
| | - Burkhard Tümmler
- Klinische Forschergruppe, OE 6710, Medizinische Hochschule Hannover, D-30625 Hannover, Germany
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88
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Chen PR, He C. Selective recognition of metal ions by metalloregulatory proteins. Curr Opin Chem Biol 2008; 12:214-21. [PMID: 18258210 DOI: 10.1016/j.cbpa.2007.12.010] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2007] [Accepted: 12/18/2007] [Indexed: 11/25/2022]
Abstract
Significant advances have been made over the past decade on illustrating structural and functional features underneath the selective metal ion recognition by various proteins in nature. These efforts led to fruitful information regarding mechanisms that bacteria employed on the regulation, transportation, and utilization of main group and essential transition metal ions, and the detoxification of hazardous heavy metal ions. Here we summarize the recent advancement on the understanding of selective recognition of transition and heavy metal ions by metalloregulatory proteins. An emphasis is placed on demonstrating the molecular level mechanism of selective metal ion recognition in bacteria. Other types of metal sensory proteins will also be briefly reviewed.
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Affiliation(s)
- Peng R Chen
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA
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89
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Rhizoremediation of Cadmium Soil Using a Cadmium-Resistant Plant Growth-Promoting Rhizopseudomonad. Curr Microbiol 2008; 56:403-7. [DOI: 10.1007/s00284-008-9099-7] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 11/06/2007] [Indexed: 11/26/2022]
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90
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Huang A, Chen H, Chen L, Dai Y, Zhao J. Effects of Cd(II) and cu(II) on microbial characteristics in 2-chlorophenol-degradation anaerobic bioreactors. J Environ Sci (China) 2008; 20:745-752. [PMID: 18763571 DOI: 10.1016/s1001-0742(08)62122-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The effects of Cd2+ and Cu2+ at 300 mg/L on anaerobic microbial communities that degrade 2-cholorophenol (2-CP) were examined. Based on the polymerase chain reaction (PCR) of 16S rDNA, bacterial community diversity and archaeal community structure were analyzed with denaturing gradient gel electrophoresis (DGGE) and cloning, respectively. Degradation capabilities of the anaerobic microbial community were drastically abated and the degradation efficiency of 2-CP was reduced to 60% after shock by Cu2+ and Cd2+, respectively. The bacterial community structure was disturbed and the biodiversity was reduced after shock by Cu2+ and Cd2+ for 3 d. Some new metal-resistant microbes which could cope with the new condition appeared. The sequence analysis showed that there existed common Archaea species in control sludge and systems when treated with Cu2+ and Cd2+, such as Methanothrix soehngenii, Methanosaeta concilii, uncultured euryarchaeote, and so on. Both the abundance and diversity of archaeal species were altered with addition of Cd2+ and Cu2+ at high concentration. Although the abundance of the predominant archaeal species decreased with Cd2+ and Cu2+ addition for 3 d, they recovered to some extent after 10 d. The diversity of archaeal species was remarkably reduced after recovery for 10 d and the shift in archaeal composition seemed to be irreversible. The 2-CP-degradation anaerobic system was more sensitive to Cu2+ than Cd2+.
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Affiliation(s)
- Aiqun Huang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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91
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Interplay of different transporters in the mediation of divalent heavy metal resistance in Pseudomonas putida KT2440. J Bacteriol 2007; 190:2680-9. [PMID: 18065533 DOI: 10.1128/jb.01494-07] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
According to in silico analysis, the genome of Pseudomonas putida KT2440 encodes at least four Zn/Cd/Pb efflux transporters-two P-type ATPases (CadA1 and CadA2) and two czc chemiosmotic transporters (CzcCBA1 and CzcCBA2). In this study we showed that all these transporters are functional, but under laboratory conditions only two of them were involved in the mediation of heavy metal resistance in P. putida KT2440. CadA2 conferred Cd(2+) and Pb(2+) resistance, whereas CzcCBA1 was involved in export of Zn(2+), Cd(2+), and possibly Pb(2+). CadA1, although nonfunctional in P. putida, improved Zn(2+) resistance and slightly improved Cd(2+) resistance when it was expressed in Escherichia coli. CzcCBA2 contributed to Zn resistance of a czcA1-defective P. putida strain or when the CzcA2 subunit was overexpressed in a transporter-deficient strain. It seemed that CzcA2 could complex with CzcC1 and CzcB1 subunits and therefore complement the loss of CzcA1. The CzcCBA2 transporter itself, however, did not function. Expression of cadA1, cadA2, and czcCBA1 was induced by heavy metals, and the expression levels were dependent on the growth medium and growth phase. Expression of cadA2 and czcCBA1 was nonspecific; both genes were induced by Zn(2+), Cd(2+), Pb(2+), Ni(2+), Co(2+), and Hg(2+). On the other hand, remarkably, expression of cadA1 was induced only by Zn(2+). Possible roles of distinct but simultaneously functioning transporters are discussed.
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92
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Abstract
A cadmium-resistant bacterium Pseudomonas putida CD2 was isolated from sewage sludge samples. Strain CD2 exhibited high maximal tolerant concentrations (MTC) for a large spectrum of divalent metals. Screening a library obtained using Tn5-B21 insertion mutagenesis resulted in identification of 12 mutants with a substantial decrease in resistance to 3 mM cadmium. The DNA sequences of the contiguous region from the Tn5 insertion sites were determined by inverse PCR. Six genes involved in cadmium resistance were identified. These genes were from three gene clusters: czcCBA1, cadA2R and colRS. The homologs of the first two gene clusters were predicted to be metal efflux systems, whereas the products of colRS, ColR and ColS, were thought to be a two-component signal transduction (TCST) system. In this study, we have demonstrated that ColRS also function in regulating multi-metal resistance using genetic complementation.
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Affiliation(s)
- Nan Hu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
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93
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Permina EA, Kazakov AE, Kalinina OV, Gelfand MS. Comparative genomics of regulation of heavy metal resistance in Eubacteria. BMC Microbiol 2006; 6:49. [PMID: 16753059 PMCID: PMC1526738 DOI: 10.1186/1471-2180-6-49] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2005] [Accepted: 06/05/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Heavy metal resistance (HMR) in Eubacteria is regulated by a variety of systems including transcription factors from the MerR family (COG0789). The HMR systems are characterized by the complex signal structure (strong palindrome within a 19 or 20 bp promoter spacer), and usually consist of transporter and regulator genes. Some HMR regulons also include detoxification systems. The number of sequenced bacterial genomes is constantly increasing and even though HMR resistance regulons of the COG0789 type usually consist of few genes per genome, the computational analysis may contribute to the understanding of the cellular systems of metal detoxification. RESULTS We studied the mercury (MerR), copper (CueR and HmrR), cadmium (CadR), lead (PbrR), and zinc (ZntR) resistance systems and demonstrated that combining protein sequence analysis and analysis of DNA regulatory signals it was possible to distinguish metal-dependent members of COG0789, assign specificity towards particular metals to uncharacterized loci, and find new genes involved in the metal resistance, in particular, multicopper oxidase and copper chaperones, candidate cytochromes from the copper regulon, new cadmium transporters and, possibly, glutathione-S-transferases. CONCLUSION Our data indicate that the specificity of the COG0789 systems can be determined combining phylogenetic analysis and identification of DNA regulatory sites. Taking into account signal structure, we can adequately identify genes that are activated using the DNA bending-unbending mechanism. In the case of regulon members that do not reside in single loci, analysis of potential regulatory sites could be crucial for the correct annotation and prediction of the specificity.
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Affiliation(s)
- EA Permina
- State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnyj proezd, 1, Moscow, 113535, Russia
| | - AE Kazakov
- Institute for Information Transmission Problems, Russian Academy of Science, Bolshoi Karetny per. 19, Moscow 127994, Russia
| | - OV Kalinina
- Department of Bioengineering and Bioinformatics, Moscow State University, Laboratory Building B, Vorobiovy Gory 1-73, Moscow 119992, Russia
| | - MS Gelfand
- Institute for Information Transmission Problems, Russian Academy of Science, Bolshoi Karetny per. 19, Moscow 127994, Russia
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94
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Wu CH, Wood TK, Mulchandani A, Chen W. Engineering plant-microbe symbiosis for rhizoremediation of heavy metals. Appl Environ Microbiol 2006; 72:1129-34. [PMID: 16461658 PMCID: PMC1392951 DOI: 10.1128/aem.72.2.1129-1134.2006] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The use of plants for rehabilitation of heavy-metal-contaminated environments is an emerging area of interest because it provides an ecologically sound and safe method for restoration and remediation. Although a number of plant species are capable of hyperaccumulation of heavy metals, the technology is not applicable for remediating sites with multiple contaminants. A clever solution is to combine the advantages of microbe-plant symbiosis within the plant rhizosphere into an effective cleanup technology. We demonstrated that expression of a metal-binding peptide (EC20) in a rhizobacterium, Pseudomonas putida 06909, not only improved cadmium binding but also alleviated the cellular toxicity of cadmium. More importantly, inoculation of sunflower roots with the engineered rhizobacterium resulted in a marked decrease in cadmium phytotoxicity and a 40% increase in cadmium accumulation in the plant root. Owing to the significantly improved growth characteristics of both the rhizobacterium and plant, the use of EC20-expressing P. putida endowed with organic-degrading capabilities may be a promising strategy to remediate mixed organic-metal-contaminated sites.
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Affiliation(s)
- Cindy H Wu
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA
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95
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Kassab DM, Roane TM. Differential responses of a mine tailings Pseudomonas isolate to cadmium and lead exposures. Biodegradation 2006; 17:379-87. [PMID: 16477362 DOI: 10.1007/s10532-005-9010-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Accepted: 08/04/2005] [Indexed: 10/25/2022]
Abstract
We examined cadmium and lead resistance in Pseudomonas sp. S8A, an isolate obtained from mine tailings-contaminated soil. Resistant to soluble metal concentrations up to 200 mg l(-1) cadmium and 300 mg l(-1) lead, S8A produced both exopolymer and biosurfactant. Upon growth, this pseudomonad diverged into two morphologically distinct colony subtypes; small and round or large and flat. In the presence of lead and in the no metal control the large morphotype appeared only in late stationary phase. With cadmium the large morphotype appeared immediately following exposure. Results show that the large morphotype produced greater amounts of surfactant than the small morphotype, suggesting a unique subpopulation response to cadmium toxicity. Results also indicate that an unidentified 28 kDa protein was expressed following exposure to >10 mg l(-1) cadmium. This study demonstrates new links between surfactant production, differential subpopulation response and metal exposure.
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Affiliation(s)
- Duried M Kassab
- Department of Biology, University of Colorado at Denver, Denver, USA
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96
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Coombs JM, Barkay T. New findings on evolution of metal homeostasis genes: evidence from comparative genome analysis of bacteria and archaea. Appl Environ Microbiol 2005; 71:7083-91. [PMID: 16269744 PMCID: PMC1287752 DOI: 10.1128/aem.71.11.7083-7091.2005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In order to examine the natural history of metal homeostasis genes in prokaryotes, open reading frames with homology to characterized P(IB)-type ATPases from the genomes of 188 bacteria and 22 archaea were investigated. Major findings were as follows. First, a high diversity in N-terminal metal binding motifs was observed. These motifs were distributed throughout bacterial and archaeal lineages, suggesting multiple loss and acquisition events. Second, the CopA locus separated into two distinct phylogenetic clusters, CopA1, which contained ATPases with documented Cu(I) influx activity, and CopA2, which contained both efflux and influx transporters and spanned the entire diversity of the bacterial domain, suggesting that CopA2 is the ancestral locus. Finally, phylogentic incongruences between 16S rRNA and P(IB)-type ATPase gene trees identified at least 14 instances of lateral gene transfer (LGT) that had occurred among diverse microbes. Results from bootstrapped supported nodes indicated that (i) a majority of the transfers occurred among proteobacteria, most likely due to the phylogenetic relatedness of these organisms, and (ii) gram-positive bacteria with low moles percent G+C were often involved in instances of LGT. These results, together with our earlier work on the occurrence of LGT in subsurface bacteria (J. M. Coombs and T. Barkay, Appl. Environ. Microbiol. 70:1698-1707, 2004), indicate that LGT has had a minor role in the evolution of P(IB)-type ATPases, unlike other genes that specify survival in metal-stressed environments. This study demonstrates how examination of a specific locus across microbial genomes can contribute to the understanding of phenotypes that are critical to the interactions of microbes with their environment.
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Affiliation(s)
- J M Coombs
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, New Jersey 08901, USA.
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97
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Manal MA, El-Naggar S, El-Aasar A, Barakat Khlood I. Bioremediation of crystal violet using air bubble bioreactor packed with Pseudomonas aeruginosa. WATER RESEARCH 2005; 39:5045-54. [PMID: 16316674 DOI: 10.1016/j.watres.2004.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Revised: 05/28/2004] [Accepted: 06/17/2004] [Indexed: 05/05/2023]
Abstract
Seven water and sediment samples were collected and tested for decolorizing crystal violet. Pseudomonas aeruginosa was the most effective isolate for dye decolorization. The LC50 of the crystal violet (115 mg/l) was measured using Artemia salina as a biomarker. The effect of different heavy metals on crystal violet decolorization was investigated. Cd2+ and Fe3+ ions showed marginal enhancement of the decolorization process, the rate was 1.35 mg/l/h compared to (1.25 mg/l/h) for the control. Phenol and m-cresol showed no effect on crystal violet decolorization, meanwhile p-cresol and p-nitrophenol reduced the decolorization rate to 1.07 and 0.01 mg/l/h, respectively. P. aeruginosa cells were immobilized by entrapment in agar-alginate beads. The beads were cultivated and reused in Erlenmeyer flask and in an air bubble column bioreactor and they enhanced the crystal violet decolorization rate to 3.33 and 7.5 mg/l/h, respectively.
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Affiliation(s)
- M A Manal
- Microbiology Laboratory, Marine Environmental Department, National Institute of Oceanography and Fisheries, Kaiyet Bay, El-Anfoshy, Alexandria, Egypt.
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98
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Kidd SP, Potter AJ, Apicella MA, Jennings MP, McEwan AG. NmlR of Neisseria gonorrhoeae: a novel redox responsive transcription factor from the MerR family. Mol Microbiol 2005; 57:1676-89. [PMID: 16135233 DOI: 10.1111/j.1365-2958.2005.04773.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A MerR-like regulator (NmlR -Neisseria merR-like Regulator) identified in the Neisseria gonorrhoeae genome lacks the conserved cysteines known to bind metal ions in characterized proteins of this family. Phylogenetic analysis indicates that NmlR defines a subfamily of MerR-like transcription factors with a distinctive pattern of conserved cysteines within their primary structure. NmlR regulates itself and three other genes in N. gonorrhoeae encoding a glutathione-dependent dehydrogenase (AdhC), a CPx-type ATPase (CopA) and a thioredoxin reductase (TrxB). An nmlR mutant lacked the ability to survive oxidative stress induced by diamide and cumene hydroperoxide. It also had > 50-fold lower NADH-S-nitrosoglutathione oxidoreductase activity consistent with a role for AdhC in protection against nitric oxide stress. The upstream sequences of the NmlR regulated genes contained typical MerR-like operator/promoter arrangements consisting of a dyad symmetry located between the -35 and -10 elements of the target genes. The NmlR target operator/promoters were cloned into a beta-galactosidase reporter system and promoter activity was repressed by the introduction of NmlR in trans. Promoter activity was activated by NmlR in the presence of diamide. Under metal depleted conditions NmlR did not repress P(AdhC) (or P(CopA)) promoter activity, but this was reversed in the presence of Zn(II), indicating repression was Zn(II)-dependent. Analysis of mutated promoters lacking the dyad symmetry revealed constitutive promoter activity which was independent of NmlR. Gel shift assays further confirmed that NmlR bound to the target promoters possessing the dyad symmetry. Site-directed mutagenesis of the four NmlR cysteine residues revealed that they were essential for activation of gene expression by NmlR.
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Affiliation(s)
- Stephen P Kidd
- Centre for Metals in Biology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Qld 4072, Australia
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Moore CM, Gaballa A, Hui M, Ye RW, Helmann JD. Genetic and physiological responses of Bacillus subtilis to metal ion stress. Mol Microbiol 2005; 57:27-40. [PMID: 15948947 DOI: 10.1111/j.1365-2958.2005.04642.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Metal ion homeostasis is regulated principally by metalloregulatory proteins that control metal ion uptake, storage and efflux genes. We have used transcriptional profiling to survey Bacillus subtilis for genes that are rapidly induced by exposure to high levels of metal ions including Ag(I), Cd(II), Cu(II), Ni(II) and Zn(II) and the metalloid As(V). Many of the genes affected by metal stress were controlled by known metalloregulatory proteins (Fur, MntR, PerR, ArsR and CueR). Additional metal-induced genes are regulated by two newly defined metal-sensing ArsR/SmtB family repressors: CzrA and AseR. CzrA represses the CadA efflux ATPase and the cation diffusion facilitator CzcD and this repression is alleviated by Zn(II), Cd(II), Co(II), Ni(II) and Cu. CadA is the major determinant for Cd(II) resistance, while CzcD protects the cell against elevated levels of Zn(II), Cu, Co(II) and Ni(II). AseR negatively regulates itself and AseA, an As(III) efflux pump which contributes to arsenite resistance in cells lacking a functional ars operon. Our results extend the range of identified effectors for the As(III)-sensor ArsR to include Cd(II) and Ag(I) and for the Cu-sensor CueR to include Ag(I) and, weakly, Cd(II) and Zn(II). In addition to systems dedicated to metal homeostasis, specific metal stresses also strongly induced pathways related to cysteine, histidine and arginine metabolism.
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Affiliation(s)
- Charles M Moore
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
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100
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Naz N, Young HK, Ahmed N, Gadd GM. Cadmium accumulation and DNA homology with metal resistance genes in sulfate-reducing bacteria. Appl Environ Microbiol 2005; 71:4610-8. [PMID: 16085855 PMCID: PMC1183370 DOI: 10.1128/aem.71.8.4610-4618.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2004] [Accepted: 02/28/2005] [Indexed: 11/20/2022] Open
Abstract
Cadmium resistance (0.1 to 1.0 mM) was studied in four pure and one mixed culture of sulfate-reducing bacteria (SRB). The growth of the bacteria was monitored with respect to carbon source (lactate) oxidation and sulfate reduction in the presence of various concentrations of cadmium chloride. Two strains Desulfovibrio desulfuricans DSM 1926 and Desulfococcus multivorans DSM 2059 showed the highest resistance to cadmium (0.5 mM). Transmission electron microscopy of the two strains showed intracellular and periplasmic accumulation of cadmium. Dot blot DNA hybridization using the probes for the smtAB, cadAC, and cadD genes indicated the presence of similar genetic determinants of heavy metal resistance in the SRB tested. DNA sequencing of the amplified DNA showed strong nucleotide homology in all the SRB strains with the known smtAB genes encoding synechococcal metallothioneins. Protein homology with the known heavy metal-translocating ATPases was also detected in the cloned amplified DNA of Desulfomicrobium norvegicum I1 and Desulfovibrio desulfuricans DSM 1926, suggesting the presence of multiple genetic mechanisms of metal resistance in the two strains.
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Affiliation(s)
- Naghma Naz
- Division of Environmental and Applied Biology, Biological Sciences Institute, School of Life Sciences, University of Dundee, Dundee DD1 4HN, Scotland, United Kingdom.
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