1
|
Viacava K, Meibom KL, Ortega D, Dyer S, Gelb A, Falquet L, Minton NP, Mestrot A, Bernier-Latmani R. Variability in Arsenic Methylation Efficiency across Aerobic and Anaerobic Microorganisms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14343-14351. [PMID: 33125231 DOI: 10.1021/acs.est.0c03908] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Microbially-mediated methylation of arsenic (As) plays an important role in the As biogeochemical cycle, particularly in rice paddy soils where methylated As, generated microbially, is translocated into rice grains. The presence of the arsenite (As(III)) methyltransferase gene (arsM) in soil microbes has been used as an indication of their capacity for As methylation. Here, we evaluate the ability of seven microorganisms encoding active ArsM enzymes to methylate As. Amongst those, only the aerobic species were efficient methylators. The anaerobic microorganisms presented high resistance to As exposure, presumably through their efficient As(III) efflux, but methylated As poorly. The only exception were methanogens, for which efficient As methylation was seemingly an artifact of membrane disruption. Deletion of an efflux pump gene (acr3) in one of the anaerobes, Clostridium pasteurianum, rendered the strain sensitive to As and capable of more efficiently methylating As. Our results led to the following conclusions: (i) encoding a functional ArsM enzyme does not guarantee that a microorganism will actively drive As methylation in the presence of the metalloid and (ii) there is an inverse relationship between efficient microbial As efflux and its methylation, because the former prevents the intracellular accumulation of As.
Collapse
Affiliation(s)
- Karen Viacava
- Environmental Microbiology Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Karin Lederballe Meibom
- Environmental Microbiology Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - David Ortega
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, NG7 2RD, Nottingham, United Kingdom
| | - Shannon Dyer
- Environmental Microbiology Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Arnaud Gelb
- Laboratory for Environmental Biotechnology, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Leia Falquet
- Environmental Microbiology Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, NG7 2RD, Nottingham, United Kingdom
| | - Adrien Mestrot
- Institute of Geography, University of Bern, 3012, Bern, Switzerland
| | - Rizlan Bernier-Latmani
- Environmental Microbiology Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| |
Collapse
|
2
|
Gupta A, Venkataraman B, Vasudevan M, Gopinath Bankar K. Co-expression network analysis of toxin-antitoxin loci in Mycobacterium tuberculosis reveals key modulators of cellular stress. Sci Rep 2017; 7:5868. [PMID: 28724903 PMCID: PMC5517426 DOI: 10.1038/s41598-017-06003-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 06/07/2017] [Indexed: 11/09/2022] Open
Abstract
Research on toxin-antitoxin loci (TA loci) is gaining impetus due to their ubiquitous presence in bacterial genomes and their observed roles in stress survival, persistence and drug tolerance. The present study investigates the expression profile of all the seventy-nine TA loci found in Mycobacterium tuberculosis. The bacterium was subjected to multiple stress conditions to identify key players of cellular stress response and elucidate a TA-coexpression network. This study provides direct experimental evidence for transcriptional activation of each of the seventy-nine TA loci following mycobacterial exposure to growth-limiting environments clearly establishing TA loci as stress-responsive modules in M. tuberculosis. TA locus activation was found to be stress-specific with multiple loci activated in a duration-based response to a particular stress. Conditions resulting in arrest of cellular translation led to greater up-regulation of TA genes suggesting that TA loci have a primary role in arresting translation in the cell. Our study identifed higBA2 and vapBC46 as key loci that were activated in all the conditions tested. Besides, relBE1, higBA3, vapBC35, vapBC22 and higBA1 were also upregulated in multpile stresses. Certain TA modules exhibited co-activation across multiple conditions suggestive of a common regulatory mechanism.
Collapse
Affiliation(s)
- Amita Gupta
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India. .,Department of Biochemistry and Centre for Innovation in Infectious Diseases Research, Education and Training (CIIDRET), University of Delhi South Campus, New Delhi, 110021, India.
| | - Balaji Venkataraman
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Madavan Vasudevan
- Genome Informatics Research Group, Bionivid Technology Pvt Ltd, Bengaluru, 560043, India
| | - Kiran Gopinath Bankar
- Genome Informatics Research Group, Bionivid Technology Pvt Ltd, Bengaluru, 560043, India
| |
Collapse
|
3
|
Draft Genome Sequence of Bacillus sp. Strain CDB3, an Arsenic-Resistant Soil Bacterium Isolated from Cattle Dip Sites. GENOME ANNOUNCEMENTS 2017. [PMID: 28642376 PMCID: PMC5481582 DOI: 10.1128/genomea.00429-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Bacillus sp. strain CDB3, isolated from cattle dip sites in Australia, is highly resistant to arsenic. It contains 22 arsenic resistance (ars) genes, of which 17 are organized in 3 ars clusters. Here, we report the draft genome sequence of CDB3, which will assist us in understanding the overall ars mechanism.
Collapse
|
4
|
Saha RP, Samanta S, Patra S, Sarkar D, Saha A, Singh MK. Metal homeostasis in bacteria: the role of ArsR-SmtB family of transcriptional repressors in combating varying metal concentrations in the environment. Biometals 2017; 30:459-503. [PMID: 28512703 DOI: 10.1007/s10534-017-0020-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 05/09/2017] [Indexed: 02/02/2023]
Abstract
Bacterial infections cause severe medical problems worldwide, resulting in considerable death and loss of capital. With the ever-increasing rise of antibiotic-resistant bacteria and the lack of development of new antibiotics, research on metal-based antimicrobial therapy has now gained pace. Metal ions are essential for survival, but can be highly toxic to organisms if their concentrations are not strictly controlled. Through evolution, bacteria have acquired complex metal-management systems that allow them to acquire metals that they need for survival in different challenging environments while evading metal toxicity. Metalloproteins that controls these elaborate systems in the cell, and linked to key virulence factors, are promising targets for the anti-bacterial drug development. Among several metal-sensory transcriptional regulators, the ArsR-SmtB family displays greatest diversity with several distinct metal-binding and nonmetal-binding motifs that have been characterized. These prokaryotic metolloregulatory transcriptional repressors represses the expression of operons linked to stress-inducing concentrations of metal ions by directly binding to the regulatory regions of DNA, while derepression results from direct binding of metal ions by these homodimeric proteins. Many bacteria, e.g., Mycobacterium tuberculosis, Bacillus anthracis, etc., have evolved to acquire multiple metal-sensory motifs which clearly demonstrate the importance of regulating concentrations of multiple metal ions. Here, we discussed the mechanisms of how ArsR-SmtB family regulates the intracellular bioavailability of metal ions both inside and outside of the host. Knowledge of the metal-challenges faced by bacterial pathogens and their survival strategies will enable us to develop the next generation drugs.
Collapse
Affiliation(s)
- Rudra P Saha
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India.
| | - Saikat Samanta
- Department of Microbiology, School of Science, Adamas University, Kolkata, 700126, India
| | - Surajit Patra
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| | - Diganta Sarkar
- Department of Biotechnology, Techno India University, Kolkata, 700091, India
| | - Abinit Saha
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| | - Manoj Kumar Singh
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| |
Collapse
|