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Willemin MS, Hamelin R, Armand F, Holliger C, Maillard J. Proteome adaptations of the organohalide-respiring Desulfitobacterium hafniense strain DCB-2 to various energy metabolisms. Front Microbiol 2023; 14:1058127. [PMID: 36733918 PMCID: PMC9888536 DOI: 10.3389/fmicb.2023.1058127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/02/2023] [Indexed: 01/18/2023] Open
Abstract
Introduction Desulfitobacterium hafniense was isolated for its ability to use organohalogens as terminal electron acceptors via organohalide respiration (OHR). In contrast to obligate OHR bacteria, Desulfitobacterium spp. show a highly versatile energy metabolism with the capacity to use different electron donors and acceptors and to grow fermentatively. Desulfitobacterium genomes display numerous and apparently redundant members of redox enzyme families which confirm their metabolic potential. Nonetheless, the enzymes responsible for many metabolic traits are not yet identified. Methods In the present work, we conducted an extended proteomic study by comparing the proteomes of Desulfitobacterium hafniense strain DCB-2 cultivated in combinations of electron donors and acceptors, triggering five alternative respiratory metabolisms that include OHR, as well as fermentation. Tandem Mass Tag labelling proteomics allowed us to identify and quantify almost 60% of the predicted proteome of strain DCB-2 (2,796 proteins) in all six growth conditions. Raw data are available via ProteomeXchange with identifier PXD030393. Results and discussion This dataset was analyzed in order to highlight the proteins that were significantly up-regulated in one or a subset of growth conditions and to identify possible key players in the different energy metabolisms. The addition of sodium sulfide as reducing agent in the medium - a very widespread practice in the cultivation of strictly anaerobic bacteria - triggered the expression of the dissimilatory sulfite reduction pathway in relatively less favorable conditions such as fermentative growth on pyruvate, respiration with H2 as electron donor and OHR conditions. The presence of H2, CO2 and acetate in the medium induced several metabolic pathways involved in carbon metabolism including the Wood-Ljungdahl pathway and two pathways related to the fermentation of butyrate that rely on electron-bifurcating enzymes. While the predicted fumarate reductase appears to be constitutively expressed, a new lactate dehydrogenase and lactate transporters were identified. Finally, the OHR metabolism with 3-chloro-4-hydroxyphenylacetate as electron acceptor strongly induced proteins encoded in several reductive dehalogenase gene clusters, as well as four new proteins related to corrinoid metabolism. We believe that this extended proteomic database represents a new landmark in understanding the metabolic versatility of Desulfitobacterium spp. and provides a solid basis for addressing future research questions.
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Affiliation(s)
- Mathilde Stéphanie Willemin
- Laboratory for Environmental Biotechnology (LBE), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Romain Hamelin
- Proteomic Core Facility (PCF), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Florence Armand
- Proteomic Core Facility (PCF), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Christof Holliger
- Laboratory for Environmental Biotechnology (LBE), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Julien Maillard
- Laboratory for Environmental Biotechnology (LBE), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland,*Correspondence: Julien Maillard, ✉
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Kundu K, Melsbach A, Heckel B, Schneidemann S, Kanapathi D, Marozava S, Merl-Pham J, Elsner M. Linking Increased Isotope Fractionation at Low Concentrations to Enzyme Activity Regulation: 4-Cl Phenol Degradation by Arthrobacter chlorophenolicus A6. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:3021-3032. [PMID: 35148097 PMCID: PMC8892832 DOI: 10.1021/acs.est.1c04939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 01/23/2022] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Slow microbial degradation of organic trace chemicals ("micropollutants") has been attributed to either downregulation of enzymatic turnover or rate-limiting substrate supply at low concentrations. In previous biodegradation studies, a drastic decrease in isotope fractionation of atrazine revealed a transition from rate-limiting enzyme turnover to membrane permeation as a bottleneck when concentrations fell below the Monod constant of microbial growth. With degradation of the pollutant 4-chlorophenol (4-CP) by Arthrobacter chlorophenolicus A6, this study targeted a bacterium which adapts its enzyme activity to concentrations. Unlike with atrazine degradation, isotope fractionation of 4-CP increased at lower concentrations, from ε(C) = -1.0 ± 0.5‰ in chemostats (D = 0.090 h-1, 88 mg L-1) and ε(C) = -2.1 ± 0.5‰ in batch (c0 = 220 mg L-1) to ε(C) = -4.1 ± 0.2‰ in chemostats at 90 μg L-1. Surprisingly, fatty acid composition indicated increased cell wall permeability at high concentrations, while proteomics revealed that catabolic enzymes (CphCI and CphCII) were differentially expressed at D = 0.090 h-1. These observations support regulation on the enzyme activity level─through either a metabolic shift between catabolic pathways or decreased enzymatic turnover at low concentrations─and, hence, reveal an alternative end-member scenario for bacterial adaptation at low concentrations. Including more degrader strains into this multidisciplinary analytical approach offers the perspective to build a knowledge base on bottlenecks of bioremediation at low concentrations that considers bacterial adaptation.
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Affiliation(s)
- Kankana Kundu
- Institute
of Groundwater Ecology, Helmholtz Zentrum
Munchen, Ingolstadter
Landstraße 1, 85764 Neuherberg, Bavaria, Germany
- Center
for Microbial Ecology and Technology (CMET), Faculty of Bioscience
Engineering, University of Ghent, Coupure Links 653, 9000 Ghent, Belgium
| | - Aileen Melsbach
- Institute
of Groundwater Ecology, Helmholtz Zentrum
Munchen, Ingolstadter
Landstraße 1, 85764 Neuherberg, Bavaria, Germany
- Chair
of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstr. 4, D-85748 Garching, Germany
| | - Benjamin Heckel
- Institute
of Groundwater Ecology, Helmholtz Zentrum
Munchen, Ingolstadter
Landstraße 1, 85764 Neuherberg, Bavaria, Germany
| | - Sarah Schneidemann
- Institute
of Groundwater Ecology, Helmholtz Zentrum
Munchen, Ingolstadter
Landstraße 1, 85764 Neuherberg, Bavaria, Germany
| | - Dheeraj Kanapathi
- Institute
of Groundwater Ecology, Helmholtz Zentrum
Munchen, Ingolstadter
Landstraße 1, 85764 Neuherberg, Bavaria, Germany
| | - Sviatlana Marozava
- Institute
of Groundwater Ecology, Helmholtz Zentrum
Munchen, Ingolstadter
Landstraße 1, 85764 Neuherberg, Bavaria, Germany
| | - Juliane Merl-Pham
- Core
Facility Proteomics, Helmholtz Zentrum München, Heidemannstr. 1, 80939 Munich, Germany
| | - Martin Elsner
- Institute
of Groundwater Ecology, Helmholtz Zentrum
Munchen, Ingolstadter
Landstraße 1, 85764 Neuherberg, Bavaria, Germany
- Chair
of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstr. 4, D-85748 Garching, Germany
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Marozava S, Merl-Pham J, Müller H, Meckenstock RU. Adaptation of Carbon Source Utilization Patterns of Geobacter metallireducens During Sessile Growth. Front Microbiol 2020; 11:1271. [PMID: 32655526 PMCID: PMC7324539 DOI: 10.3389/fmicb.2020.01271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/19/2020] [Indexed: 11/13/2022] Open
Abstract
There are two main strategies known how microorganisms regulate substrate utilization: specialization on one preferred substrate at high concentrations in batch cultures or simultaneous utilization of many substrates at low concentrations in chemostats. However, it remains unclear how microorganisms utilize substrates at low concentrations in the subsurface: do they focus on a single substrate and exhibit catabolite repression or do they de-repress regulation of all catabolic pathways? Here, we investigated the readiness of Geobacter metallireducens to degrade organic substrates under sessile growth in sediment columns in the presence of a mixed community as a model for aquifers. Three parallel columns were filled with sand and flushed with anoxic medium at a constant inflow (18 ml h-1) of the substrate benzoate (1 mM) with non-limiting nitrate concentrations (30 mM) as electron acceptor. Columns were inoculated with the anaerobic benzoate degrader G. metallireducens. Microbial degradation produced concentration gradients of benzoate toward the column outlet. Metagenomics and label-free metaproteomics were used to detect and quantify the protein expression of G. metallireducens. Bulk benzoate concentrations below 0.2 mM led to increased abundance of catabolic proteins involved in utilization of fermentation products and aromatic compounds including the complete upregulation of the toluene-degrading pathway although toluene was not added to the medium. We propose that under sessile conditions and low substrate concentrations G. metallireducens expresses a specific set of catabolic pathways for preferred substrates, even when these substrates are not present.
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Affiliation(s)
- Sviatlana Marozava
- Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Juliane Merl-Pham
- Research Unit Protein Science, Helmholtz Zentrum München, Neuherberg, Germany
| | - Hubert Müller
- Environmental Microbiology and Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Rainer U. Meckenstock
- Environmental Microbiology and Biotechnology, University of Duisburg-Essen, Essen, Germany
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