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Lin J, Xiao Y, Liu H, Gao D, Duan Y, Zhu X. Combined transcriptomic and pangenomic analyses guide metabolic amelioration to enhance tiancimycins production. Appl Microbiol Biotechnol 2024; 108:18. [PMID: 38170317 DOI: 10.1007/s00253-023-12937-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 11/15/2023] [Accepted: 11/26/2023] [Indexed: 01/05/2024]
Abstract
Exploration of high-yield mechanism is important for further titer improvement of valuable antibiotics, but how to achieve this goal is challenging. Tiancimycins (TNMs) are anthraquinone-fused enediynes with promising drug development potentials, but their prospective applications are limited by low titers. This work aimed to explore the intrinsic high-yield mechanism in previously obtained TNMs high-producing strain Streptomyces sp. CB03234-S for the further titer amelioration of TNMs. First, the typical ribosomal RpsL(K43N) mutation in CB03234-S was validated to be merely responsible for the streptomycin resistance but not the titer improvement of TNMs. Subsequently, the combined transcriptomic, pan-genomic and KEGG analyses revealed that the significant changes in the carbon and amino acid metabolisms could reinforce the metabolic fluxes of key CoA precursors, and thus prompted the overproduction of TNMs in CB03234-S. Moreover, fatty acid metabolism was considered to exert adverse effects on the biosynthesis of TNMs by shunting and reducing the accumulation of CoA precursors. Therefore, different combinations of relevant genes were respectively overexpressed in CB03234-S to strengthen fatty acid degradation. The resulting mutants all showed the enhanced production of TNMs. Among them, the overexpression of fadD, a key gene responsible for the first step of fatty acid degradation, achieved the highest 21.7 ± 1.1 mg/L TNMs with a 63.2% titer improvement. Our studies suggested that comprehensive bioinformatic analyses are effective to explore metabolic changes and guide rational metabolic reconstitution for further titer improvement of target products. KEY POINTS: • Comprehensive bioinformatic analyses effectively reveal primary metabolic changes. • Primary metabolic changes cause precursor enrichment to enhance TNMs production. • Strengthening of fatty acid degradation further improves the titer of TNMs.
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Affiliation(s)
- Jing Lin
- Xiangya International Academy of Translational Medicine, Central South University, Yuelu District, Tongzipo Road, #172, Changsha, 410013, Hunan, China
| | - Yu Xiao
- Xiangya International Academy of Translational Medicine, Central South University, Yuelu District, Tongzipo Road, #172, Changsha, 410013, Hunan, China
| | - Huiming Liu
- Xiangya International Academy of Translational Medicine, Central South University, Yuelu District, Tongzipo Road, #172, Changsha, 410013, Hunan, China
| | - Die Gao
- Xiangya International Academy of Translational Medicine, Central South University, Yuelu District, Tongzipo Road, #172, Changsha, 410013, Hunan, China
| | - Yanwen Duan
- Xiangya International Academy of Translational Medicine, Central South University, Yuelu District, Tongzipo Road, #172, Changsha, 410013, Hunan, China.
- Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, Changsha, 410013, Hunan, China.
- National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, Changsha, 410013, Hunan, China.
| | - Xiangcheng Zhu
- Xiangya International Academy of Translational Medicine, Central South University, Yuelu District, Tongzipo Road, #172, Changsha, 410013, Hunan, China.
- Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, Changsha, 410013, Hunan, China.
- National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, Changsha, 410013, Hunan, China.
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Kim J, Lu LC, Gao X, Hofmockel KS, Masiello CA, Silberg JJ. Using Methyl Bromide for Interspecies Cell-Cell Signaling and As a Reporter in a Model Soil Consortium. ACS Synth Biol 2023; 12:3743-3753. [PMID: 37991716 DOI: 10.1021/acssynbio.3c00559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Soil microbial communities with reduced complexity are emerging as model systems for studying consortia-scale phenotypes. To establish synthetic biology tools for studying these communities in hard-to-image environmental materials, we evaluated whether a single member of a model soil consortium (MSC) can be programmed to report on gene expression without requiring matrix disruption. For these studies, we targeted a five-membered MSC that includes Dyadobacter fermentans, Ensifer adhaerens, Rhodococcus sp003130705, Streptomyces sp001905665, and Variovorax beijingensis. By coupling the expression of a methyl halide transferase to a constitutive promoter, we show that V. beijingensis can be programmed to synthesize methyl halides that accumulate in the soil headspace at levels that are ≥24-fold higher than all other MSC members across a range of environmentally relevant hydration conditions. We find that methyl halide production can report on an MSC promoter that is activated by changes in water potential, and we demonstrate that a synthetic gas signal can be read out directly using gas chromatography and indirectly using a soil-derived Methylorubrum that is programmed to produce a visual output in response to methyl halides. These tools will be useful for future studies that investigate how MSC responds to dynamic hydration conditions, such as drought and flood events induced by climate change, which can alter soil water potential and induce the release of stored carbon.
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Affiliation(s)
- Jiwoo Kim
- Department of Biosciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
| | - Li Chieh Lu
- Department of Biosciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
| | - Xiaodong Gao
- Department of Earth, Environmental and Planetary Sciences, Rice University, 6100 Main St, MS-126, Houston, Texas 77005, United States
| | - Kirsten S Hofmockel
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Caroline A Masiello
- Department of Biosciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
- Department of Earth, Environmental and Planetary Sciences, Rice University, 6100 Main St, MS-126, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, 6100 Main Street, MS-60, Houston, Texas 77005, United States
| | - Jonathan J Silberg
- Department of Biosciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, 6100 Main Street, MS-142, Houston, Texas 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, MS-362, Houston, Texas 77005, United States
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Huang D, Xu R, Sun X, Li Y, Xiao E, Xu Z, Wang Q, Gao P, Yang Z, Lin H, Sun W. Effects of perfluorooctanoic acid (PFOA) on activated sludge microbial community under aerobic and anaerobic conditions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:63379-63392. [PMID: 35459989 DOI: 10.1007/s11356-022-18841-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Per- and polyfluoroalkyl substances (PFASs) have received increasing attention due to their widespread presence in diverse environments including wastewater treatment plants (WWTPs) and their potential adverse health effects. Perfluorooctanoic acid (PFOA) is one of the most detected forms of PFASs in WWTPs. However, there is still a paucity of knowledge about the effect of PFASs on microorganisms of the key component of WWTP, activated sludge. In this study, lab-scale microcosm experiments were established to evaluate the influences of PFOA on activated sludge microbes under aerobic and anaerobic conditions. The diversity, structure, and microbe-microbe interaction of microbial community were determined by 16S rRNA gene amplicon sequencing and co-occurrence network analysis. After 90 days of exposure to PFOA, activated sludge microbial richness decreased under both aerobic and anaerobic conditions. Specifically, under aerobic condition, Rhodopseudomonas (mean relative abundance 3.6%), Flavobacterium (2.4%), and Ignavibacterium (6.6%) were enriched in PFOA-spiked activated sludge compared with that in the unspiked sludge (2.6%, 0.1%, and 1.9%, respectively). By contrast, after 90 days of exposure to PFOA, Eubacterium (2.1%), Hyphomicrobium (1.8%), and Methyloversatilis (1.2%) were enriched under anaerobic condition, and more abundant than that in the control sludge (0.4%, 1.5%, and 0.6%, respectively). These genera were the potential PFOA-resistant members. In addition, Azospirillum and Sporomusa were the most connected taxa in PFOA-aerobic and PFOA-anaerobic networks, respectively. Prediction of the functional gene showed that PFOA inhibited some gene expression of sludge microbes, such as transcription, amino acid transport and metabolism, and energy production and conversion. In summary, continued exposure to PFOA induced substantial shifts of the sludge bacterial diversity and composition under both aerobic and anaerobic conditions.
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Affiliation(s)
- Duanyi Huang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China
- Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, People's Republic of China
| | - Rui Xu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, 808 Tianyuan Road, Guangzhou, 510650, China
| | - Xiaoxu Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, 808 Tianyuan Road, Guangzhou, 510650, China
| | - Yongbin Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, 808 Tianyuan Road, Guangzhou, 510650, China
| | - Enzong Xiao
- Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Zhimin Xu
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Qi Wang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, 808 Tianyuan Road, Guangzhou, 510650, China
| | - Pin Gao
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, 808 Tianyuan Road, Guangzhou, 510650, China
| | - Zhaohui Yang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, People's Republic of China.
- Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, People's Republic of China.
| | - Hanzhi Lin
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, 808 Tianyuan Road, Guangzhou, 510650, China.
| | - Weimin Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, 808 Tianyuan Road, Guangzhou, 510650, China.
- School of Environment, Henan Normal University, Xinxiang, China.
- Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Xinxiang, China.
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Barnum TP, Coates JD. The biogeochemical cycling of chlorine. GEOBIOLOGY 2022; 20:634-649. [PMID: 35851523 DOI: 10.1111/gbi.12513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 05/24/2022] [Accepted: 06/26/2022] [Indexed: 06/15/2023]
Abstract
Chlorine has important roles in the Earth's systems. In different forms, it helps balance the charge and osmotic potential of cells, provides energy for microorganisms, mobilizes metals in geologic fluids, alters the salinity of waters, and degrades atmospheric ozone. Despite this importance, there has not been a comprehensive summary of chlorine's geobiology. Here, we unite different areas of recent research to describe a biogeochemical cycle for chlorine. Chlorine enters the biosphere through volcanism and weathering of rocks and is sequestered by subduction and the formation of evaporite sediments from inland seas. In the biosphere, chlorine is converted between solid, dissolved, and gaseous states and in oxidation states ranging from -1 to +7, with the soluble, reduced chloride ion as its most common form. Living organisms and chemical reactions change chlorine's form through oxidation and reduction and the addition and removal of chlorine from organic molecules. Chlorine can be transported through the atmosphere, and the highest oxidation states of chlorine are produced by reactions between sunlight and trace chlorine gases. Partial oxidation of chlorine occurs across the biosphere and creates reactive chlorine species that contribute to the oxidative stress experienced by living cells. A unified view of this chlorine cycle demonstrates connections between chlorine biology, chemistry, and geology that affect life on the Earth.
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Affiliation(s)
- Tyler P Barnum
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - John D Coates
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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Genome-Wide Transcription Start Sites Mapping in Methylorubrum Grown with Dichloromethane and Methanol. Microorganisms 2022; 10:microorganisms10071301. [PMID: 35889020 PMCID: PMC9320726 DOI: 10.3390/microorganisms10071301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Dichloromethane (DCM, methylene chloride) is a toxic halogenated volatile organic compound massively used for industrial applications, and consequently often detected in the environment as a major pollutant. DCM biotransformation suggests a sustainable decontamination strategy of polluted sites. Among methylotrophic bacteria able to use DCM as a sole source of carbon and energy for growth, Methylorubrum extorquens DM4 is a longstanding reference strain. Here, the primary 5′-ends of transcripts were obtained using a differential RNA-seq (dRNA-seq) approach to provide the first transcription start site (TSS) genome-wide landscape of a methylotroph using DCM or methanol. In total, 7231 putative TSSs were annotated and classified with respect to their localization to coding sequences (CDSs). TSSs on the opposite strand of CDS (antisense TSS) account for 31% of all identified TSSs. One-third of the detected TSSs were located at a distance to the start codon inferior to 250 nt (average of 84 nt) with 7% of leaderless mRNA. Taken together, the global TSS map for bacterial growth using DCM or methanol will facilitate future studies in which transcriptional regulation is crucial, and efficient DCM removal at polluted sites is limited by regulatory processes.
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Kröber E, Kanukollu S, Wende S, Bringel F, Kolb S. A putatively new family of alphaproteobacterial chloromethane degraders from a deciduous forest soil revealed by stable isotope probing and metagenomics. ENVIRONMENTAL MICROBIOME 2022; 17:24. [PMID: 35527282 PMCID: PMC9080209 DOI: 10.1186/s40793-022-00416-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Chloromethane (CH3Cl) is the most abundant halogenated organic compound in the atmosphere and substantially responsible for the destruction of the stratospheric ozone layer. Since anthropogenic CH3Cl sources have become negligible with the application of the Montreal Protocol (1987), natural sources, such as vegetation and soils, have increased proportionally in the global budget. CH3Cl-degrading methylotrophs occurring in soils might be an important and overlooked sink. RESULTS AND CONCLUSIONS The objective of our study was to link the biotic CH3Cl sink with the identity of active microorganisms and their biochemical pathways for CH3Cl degradation in a deciduous forest soil. When tested in laboratory microcosms, biological CH3Cl consumption occurred in leaf litter, senescent leaves, and organic and mineral soil horizons. Highest consumption rates, around 2 mmol CH3Cl g-1 dry weight h-1, were measured in organic soil and senescent leaves, suggesting that top soil layers are active (micro-)biological CH3Cl degradation compartments of forest ecosystems. The DNA of these [13C]-CH3Cl-degrading microbial communities was labelled using stable isotope probing (SIP), and the corresponding taxa and their metabolic pathways studied using high-throughput metagenomics sequencing analysis. [13C]-labelled Metagenome-Assembled Genome closely related to the family Beijerinckiaceae may represent a new methylotroph family of Alphaproteobacteria, which is found in metagenome databases of forest soils samples worldwide. Gene markers of the only known pathway for aerobic CH3Cl degradation, via the methyltransferase system encoded by the CH3Cl utilisation genes (cmu), were undetected in the DNA-SIP metagenome data, suggesting that biological CH3Cl sink in this deciduous forest soil operates by a cmu-independent metabolism.
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Affiliation(s)
- Eileen Kröber
- Max-Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Saranya Kanukollu
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Sonja Wende
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Françoise Bringel
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
| | - Steffen Kolb
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
- Thaer Institute, Faculty of Life Sciences, Humboldt University of Berlin, Berlin, Germany
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Kröber E, Wende S, Kanukollu S, Buchen-Tschiskale C, Besaury L, Keppler F, Vuilleumier S, Kolb S, Bringel F. 13 C-chloromethane incubations provide evidence for novel bacterial chloromethane degraders in a living tree fern. Environ Microbiol 2021; 23:4450-4465. [PMID: 34121306 DOI: 10.1111/1462-2920.15638] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 12/20/2022]
Abstract
Chloromethane (CH3 Cl) is the most abundant halogenated volatile organic compound in the atmosphere and contributes to stratospheric ozone depletion. CH3 Cl has mainly natural sources such as emissions from vegetation. In particular, ferns have been recognized as strong emitters. Mitigation of CH3 Cl to the atmosphere by methylotrophic bacteria, a global sink for this compound, is likely underestimated and remains poorly characterized. We identified and characterized CH3 Cl-degrading bacteria associated with intact and living tree fern plants of the species Cyathea australis by stable isotope probing (SIP) with 13 C-labelled CH3 Cl combined with metagenomics. Metagenome-assembled genomes (MAGs) related to Methylobacterium and Friedmanniella were identified as being involved in the degradation of CH3 Cl in the phyllosphere, i.e., the aerial parts of the tree fern, while a MAG related to Sorangium was linked to CH3 Cl degradation in the fern rhizosphere. The only known metabolic pathway for CH3 Cl degradation, via a methyltransferase system including the gene cmuA, was not detected in metagenomes or MAGs identified by SIP. Hence, a yet uncharacterized methylotrophic cmuA-independent pathway may drive CH3 Cl degradation in the investigated tree ferns.
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Affiliation(s)
- Eileen Kröber
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Sonja Wende
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Saranya Kanukollu
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Caroline Buchen-Tschiskale
- Isotope Biogeochemistry and Gas Fluxes, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Ludovic Besaury
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
| | - Stéphane Vuilleumier
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
| | - Steffen Kolb
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany.,Thaer Institute, Faculty of Life Sciences, Humboldt University of Berlin, Berlin, Germany
| | - Françoise Bringel
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
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Maucourt B, Vuilleumier S, Bringel F. Transcriptional regulation of organohalide pollutant utilisation in bacteria. FEMS Microbiol Rev 2020; 44:189-207. [PMID: 32011697 DOI: 10.1093/femsre/fuaa002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 01/31/2020] [Indexed: 12/13/2022] Open
Abstract
Organohalides are organic molecules formed biotically and abiotically, both naturally and through industrial production. They are usually toxic and represent a health risk for living organisms, including humans. Bacteria capable of degrading organohalides for growth express dehalogenase genes encoding enzymes that cleave carbon-halogen bonds. Such bacteria are of potential high interest for bioremediation of contaminated sites. Dehalogenase genes are often part of gene clusters that may include regulators, accessory genes and genes for transporters and other enzymes of organohalide degradation pathways. Organohalides and their degradation products affect the activity of regulatory factors, and extensive genome-wide modulation of gene expression helps dehalogenating bacteria to cope with stresses associated with dehalogenation, such as intracellular increase of halides, dehalogenase-dependent acid production, organohalide toxicity and misrouting and bottlenecks in metabolic fluxes. This review focuses on transcriptional regulation of gene clusters for dehalogenation in bacteria, as studied in laboratory experiments and in situ. The diversity in gene content, organization and regulation of such gene clusters is highlighted for representative organohalide-degrading bacteria. Selected examples illustrate a key, overlooked role of regulatory processes, often strain-specific, for efficient dehalogenation and productive growth in presence of organohalides.
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Affiliation(s)
- Bruno Maucourt
- Université de Strasbourg, UMR 7156 CNRS, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Stéphane Vuilleumier
- Université de Strasbourg, UMR 7156 CNRS, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Françoise Bringel
- Université de Strasbourg, UMR 7156 CNRS, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
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Dichloromethane Degradation Pathway from Unsequenced Hyphomicrobium sp. MC8b Rapidly Explored by Pan-Proteomics. Microorganisms 2020; 8:microorganisms8121876. [PMID: 33260855 PMCID: PMC7760279 DOI: 10.3390/microorganisms8121876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/23/2022] Open
Abstract
Several bacteria are able to degrade the major industrial solvent dichloromethane (DCM) by using the conserved dehalogenase DcmA, the only system for DCM degradation characterised at the sequence level so far. Using differential proteomics, we rapidly identified key determinants of DCM degradation for Hyphomicrobium sp. MC8b, an unsequenced facultative methylotrophic DCM-degrading strain. For this, we designed a pan-proteomics database comprising the annotated genome sequences of 13 distinct Hyphomicrobium strains. Compared to growth with methanol, growth with DCM induces drastic changes in the proteome of strain MC8b. Dichloromethane dehalogenase DcmA was detected by differential pan-proteomics, but only with poor sequence coverage, suggesting atypical characteristics of the DCM dehalogenation system in this strain. More peptides were assigned to DcmA by error-tolerant search, warranting subsequent sequencing of the genome of strain MC8b, which revealed a highly divergent set of dcm genes in this strain. This suggests that the dcm enzymatic system is less strongly conserved than previously believed, and that substantial molecular evolution of dcm genes has occurred beyond their horizontal transfer in the bacterial domain. Our study showed the power of pan-proteomics for quick characterization of new strains belonging to branches of the Tree of Life that are densely genome-sequenced.
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Wang Q, Song X, Tang S, Yu L. Enhanced removal of tetrachloroethylene from aqueous solutions by biodegradation coupled with nZVI modified by layered double hydroxide. CHEMOSPHERE 2020; 243:125260. [PMID: 31734600 DOI: 10.1016/j.chemosphere.2019.125260] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/12/2019] [Accepted: 10/29/2019] [Indexed: 06/10/2023]
Abstract
Chlorinated volatile organic compounds, such as tetrachloroethylene (PCE), are the most commonly detected toxic contaminants in groundwater. In this study, the performance of PCE removal by a microbial consortium combined with nZVI modified by layered double hydroxide (nZVI-LDH) was evaluated. The enriched PCE-degrading consortium consisted of 44.49% Clostridium and other potential PCE degraders, and 0.5-2.5 mg/L PCE was completely biodegraded within 4 days. The characterization of nZVI-LDH indicated that LDH was coated on the surfaces of nZVI particles with an increased surface area. The PCE removal kinetics by nZVI-LDH was well described by a second-order model, and the removal rate constant of nZVI-LDH was 0.12 L h/mg, higher than that of native nZVI (0.02 L h/mg). Interestingly, the presence of Cu2+ improved the removal efficiency of PCE by nZVI-LDH, owing to its role as a catalyst or medium for charge transfer during reduction. Removal of PCE was enhanced by coupling the PCE-degrading consortium and nZVI-LDH. The initial removal of PCE was mainly dominated by the abiotic degradation and adsorption of nZVI-LDH, and biodegradation then played a major role in the exhaustion of nZVI-LDH. These results suggest that biodegradation coupled with nZVI-LDH has a great potential for applications in the remediation of chlorinated-solvent contaminated groundwater.
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Affiliation(s)
- Qing Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 21008, China
| | - Xin Song
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 21008, China.
| | - Shiyue Tang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 21008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lei Yu
- Department of Environmental Engineering, Nanjing Forestry University, Nanjing, 210037, China
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Jaeger N, Besaury L, Röhling AN, Koch F, Delort AM, Gasc C, Greule M, Kolb S, Nadalig T, Peyret P, Vuilleumier S, Amato P, Bringel F, Keppler F. Chloromethane formation and degradation in the fern phyllosphere. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 634:1278-1287. [PMID: 29660879 DOI: 10.1016/j.scitotenv.2018.03.316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 03/25/2018] [Accepted: 03/25/2018] [Indexed: 06/08/2023]
Abstract
Chloromethane (CH3Cl) is the most abundant halogenated trace gas in the atmosphere. It plays an important role in natural stratospheric ozone destruction. Current estimates of the global CH3Cl budget are approximate. The strength of the CH3Cl global sink by microbial degradation in soils and plants is under discussion. Some plants, particularly ferns, have been identified as substantial emitters of CH3Cl. Their ability to degrade CH3Cl remains uncertain. In this study, we investigated the potential of leaves from 3 abundant ferns (Osmunda regalis, Cyathea cooperi, Dryopteris filix-mas) to produce and degrade CH3Cl by measuring their production and consumption rates and their stable carbon and hydrogen isotope signatures. Investigated ferns are able to degrade CH3Cl at rates from 2.1 to 17 and 0.3 to 0.9μggdw-1day-1 for C. cooperi and D. filix-mas respectively, depending on CH3Cl supplementation and temperature. The stable carbon isotope enrichment factor of remaining CH3Cl was -39±13‰, whereas negligible isotope fractionation was observed for hydrogen (-8±19‰). In contrast, O. regalis did not consume CH3Cl, but produced it at rates ranging from 0.6 to 128μggdw-1day-1, with stable isotope values of -97±8‰ for carbon and -202±10‰ for hydrogen, respectively. Even though the 3 ferns showed clearly different formation and consumption patterns, their leaf-associated bacterial diversity was not notably different. Moreover, we did not detect genes associated with the only known chloromethane utilization pathway "cmu" in the microbial phyllosphere of the investigated ferns. Our study suggests that still unknown CH3Cl biodegradation processes on plants play an important role in global cycling of atmospheric CH3Cl.
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Affiliation(s)
- Nicole Jaeger
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany.
| | - Ludovic Besaury
- Institut de Chimie de Clermont-Ferrand (ICCF), UMR6096 CNRS-UCA-Sigma, Clermont-Ferrand, France; Université de Strasbourg, CNRS, GMGM UMR 7156, Department of Microbiology, Genomics and the Environment, Strasbourg, France; UMR FARE, Université de Reims Champagne Ardenne, INRA, Reims, France
| | - Amelie Ninja Röhling
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany
| | - Fabien Koch
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany
| | - Anne-Marie Delort
- Institut de Chimie de Clermont-Ferrand (ICCF), UMR6096 CNRS-UCA-Sigma, Clermont-Ferrand, France
| | - Cyrielle Gasc
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France
| | - Markus Greule
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany
| | - Steffen Kolb
- Microbial Biogeochemistry, Research Area Landscape Functioning, Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany
| | - Thierry Nadalig
- Université de Strasbourg, CNRS, GMGM UMR 7156, Department of Microbiology, Genomics and the Environment, Strasbourg, France
| | - Pierre Peyret
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France
| | - Stéphane Vuilleumier
- Université de Strasbourg, CNRS, GMGM UMR 7156, Department of Microbiology, Genomics and the Environment, Strasbourg, France
| | - Pierre Amato
- Institut de Chimie de Clermont-Ferrand (ICCF), UMR6096 CNRS-UCA-Sigma, Clermont-Ferrand, France
| | - Françoise Bringel
- Université de Strasbourg, CNRS, GMGM UMR 7156, Department of Microbiology, Genomics and the Environment, Strasbourg, France
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany; Heidelberg Center for the Environment HCE, Heidelberg University, Heidelberg, Germany.
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Chaignaud P, Morawe M, Besaury L, Kröber E, Vuilleumier S, Bringel F, Kolb S. Methanol consumption drives the bacterial chloromethane sink in a forest soil. ISME JOURNAL 2018; 12:2681-2693. [PMID: 29991765 PMCID: PMC6194010 DOI: 10.1038/s41396-018-0228-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/01/2018] [Accepted: 06/15/2018] [Indexed: 11/16/2022]
Abstract
Halogenated volatile organic compounds (VOCs) emitted by terrestrial ecosystems, such as chloromethane (CH3Cl), have pronounced effects on troposphere and stratosphere chemistry and climate. The magnitude of the global CH3Cl sink is uncertain since it involves a largely uncharacterized microbial sink. CH3Cl represents a growth substrate for some specialized methylotrophs, while methanol (CH3OH), formed in much larger amounts in terrestrial environments, may be more widely used by such microorganisms. Direct measurements of CH3Cl degradation rates in two field campaigns and in microcosms allowed the identification of top soil horizons (i.e., organic plus mineral A horizon) as the major biotic sink in a deciduous forest. Metabolically active members of Alphaproteobacteria and Actinobacteria were identified by taxonomic and functional gene biomarkers following stable isotope labeling (SIP) of microcosms with CH3Cl and CH3OH, added alone or together as the [13C]-isotopologue. Well-studied reference CH3Cl degraders, such as Methylobacterium extorquens CM4, were not involved in the sink activity of the studied soil. Nonetheless, only sequences of the cmuA chloromethane dehalogenase gene highly similar to those of known strains were detected, suggesting the relevance of horizontal gene transfer for CH3Cl degradation in forest soil. Further, CH3Cl consumption rate increased in the presence of CH3OH. Members of Alphaproteobacteria and Actinobacteria were also 13C-labeled upon [13C]-CH3OH amendment. These findings suggest that key bacterial CH3Cl degraders in forest soil benefit from CH3OH as an alternative substrate. For soil CH3Cl-utilizing methylotrophs, utilization of several one-carbon compounds may represent a competitive advantage over heterotrophs that cannot utilize one-carbon compounds.
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Affiliation(s)
- Pauline Chaignaud
- Department of Microbiology, Genomics and the Environment, Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France.,Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Mareen Morawe
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Ludovic Besaury
- Department of Microbiology, Genomics and the Environment, Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France.,UMR FARE 614 Fractionnement des AgroRessources et Environnement, Chaire AFERE, INRA, Université de Reims Champagne-Ardenne, Reims, France
| | - Eileen Kröber
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Landscape Research, Müncheberg, Germany
| | - Stéphane Vuilleumier
- Department of Microbiology, Genomics and the Environment, Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Françoise Bringel
- Department of Microbiology, Genomics and the Environment, Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France.
| | - Steffen Kolb
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Landscape Research, Müncheberg, Germany.
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N-terminome and proteogenomic analysis of the Methylobacterium extorquens DM4 reference strain for dichloromethane utilization. J Proteomics 2018; 179:131-139. [DOI: 10.1016/j.jprot.2018.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 02/28/2018] [Accepted: 03/16/2018] [Indexed: 12/29/2022]
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