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García-Franco A, Godoy P, Duque E, Ramos JL. Engineering styrene biosynthesis: designing a functional trans-cinnamic acid decarboxylase in Pseudomonas. Microb Cell Fact 2024; 23:69. [PMID: 38419048 PMCID: PMC10903017 DOI: 10.1186/s12934-024-02341-0] [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: 10/13/2023] [Accepted: 02/17/2024] [Indexed: 03/02/2024] Open
Abstract
We are interested in converting second generation feedstocks into styrene, a valuable chemical compound, using the solvent-tolerant Pseudomonas putida DOT-T1E as a chassis. Styrene biosynthesis takes place from L-phenylalanine in two steps: firstly, L-phenylalanine is converted into trans-cinnamic acid (tCA) by PAL enzymes and secondly, a decarboxylase yields styrene. This study focuses on designing and synthesizing a functional trans-cinnamic acid decarboxylase in Pseudomonas putida. To achieve this, we utilized the "wholesale" method, involving deriving two consensus sequences from multi-alignments of homologous yeast ferulate decarboxylase FDC1 sequences with > 60% and > 50% identity, respectively. These consensus sequences were used to design Pseudomonas codon-optimized genes named psc1 and psd1 and assays were conducted to test the activity in P. putida. Our results show that the PSC1 enzyme effectively decarboxylates tCA into styrene, whilst the PSD1 enzyme does not. The optimal conditions for the PSC1 enzyme, including pH and temperature were determined. The L-phenylalanine DOT-T1E derivative Pseudomonas putida CM12-5 that overproduces L-phenylalanine was used as the host for expression of pal/psc1 genes to efficiently convert L-phenylalanine into tCA, and the aromatic carboxylic acid into styrene. The highest styrene production was achieved when the pal and psc1 genes were co-expressed as an operon in P. putida CM12-5. This construction yielded styrene production exceeding 220 mg L-1. This study serves as a successful demonstration of our strategy to tailor functional enzymes for novel host organisms, thereby broadening their metabolic capabilities. This breakthrough opens the doors to the synthesis of aromatic hydrocarbons using Pseudomonas putida as a versatile biofactory.
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Affiliation(s)
- Ana García-Franco
- Estación Experimental del Zaidín. Consejo Superior de Investigaciones Científicas, c/ Profesor Albareda 1, 18008, Granada, Spain
- Programa de Doctorado en Bioquímica y Biología Molecular, Universidad de Granada, Granada, Spain
| | - Patricia Godoy
- Estación Experimental del Zaidín. Consejo Superior de Investigaciones Científicas, c/ Profesor Albareda 1, 18008, Granada, Spain
| | - Estrella Duque
- Estación Experimental del Zaidín. Consejo Superior de Investigaciones Científicas, c/ Profesor Albareda 1, 18008, Granada, Spain
| | - Juan L Ramos
- Estación Experimental del Zaidín. Consejo Superior de Investigaciones Científicas, c/ Profesor Albareda 1, 18008, Granada, Spain.
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Dodge AG, Thoma CJ, O’Connor MR, Wackett LP. Recombinant Pseudomonas growing on non-natural fluorinated substrates shows stress but overall tolerance to cytoplasmically released fluoride anion. mBio 2024; 15:e0278523. [PMID: 38063407 PMCID: PMC10790756 DOI: 10.1128/mbio.02785-23] [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: 10/13/2023] [Accepted: 10/23/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE Society uses thousands of organofluorine compounds, sometimes denoted per- and polyfluoroalkyl substances (PFAS), in hundreds of products, but recent studies have shown some to manifest human and environmental health effects. As a class, they are recalcitrant to biodegradation, partly due to the paucity of fluorinated natural products to which microbes have been exposed. Another limit to PFAS biodegradation is the intracellular toxicity of fluoride anion generated from C-F bond cleavage. The present study identified a broader substrate specificity in an enzyme originally studied for its activity on the natural product fluoroacetate. A recombinant Pseudomonas expressing this enzyme was used here as a model system to better understand the limits and effects of a high level of intracellular fluoride generation. A fluoride stress response has evolved in bacteria and has been described in Pseudomonas spp. The present study is highly relevant to organofluorine compound degradation or engineered biosynthesis in which fluoride anion is a substrate.
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Affiliation(s)
- Anthony G. Dodge
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology Institute, University of Minnesota, Twin Cities, Minnesota, USA
| | - Calvin J. Thoma
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology Institute, University of Minnesota, Twin Cities, Minnesota, USA
| | - Madeline R. O’Connor
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology Institute, University of Minnesota, Twin Cities, Minnesota, USA
| | - Lawrence P. Wackett
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology Institute, University of Minnesota, Twin Cities, Minnesota, USA
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Bertelmann C, Mock M, Schmid A, Bühler B. Efficiency aspects of regioselective testosterone hydroxylation with highly active CYP450-based whole-cell biocatalysts. Microb Biotechnol 2024; 17:e14378. [PMID: 38018939 PMCID: PMC10832557 DOI: 10.1111/1751-7915.14378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 11/12/2023] [Indexed: 11/30/2023] Open
Abstract
Steroid hydroxylations belong to the industrially most relevant reactions catalysed by cytochrome P450 monooxygenases (CYP450s) due to the pharmacological relevance of hydroxylated derivatives. The implementation of respective bioprocesses at an industrial scale still suffers from several limitations commonly found in CYP450 catalysis, that is low turnover rates, enzyme instability, inhibition and toxicity related to the substrate(s) and/or product(s). Recently, we achieved a new level of steroid hydroxylation rates by introducing highly active testosterone-hydroxylating CYP450 BM3 variants together with the hydrophobic outer membrane protein AlkL into Escherichia coli-based whole-cell biocatalysts. However, the activity tended to decrease, which possibly impedes overall productivities and final product titres. In this study, a considerable instability was confirmed and subject to a systematic investigation regarding possible causes. In-depth evaluation of whole-cell biocatalyst kinetics and stability revealed a limitation in substrate availability due to poor testosterone solubility as well as inhibition by the main product 15β-hydroxytestosterone. Instability of CYP450 BM3 variants was disclosed as another critical factor, which is of general significance for CYP450-based biocatalysis. Presented results reveal biocatalyst, reaction and process engineering strategies auguring well for industrial implementation of the developed steroid hydroxylation platform.
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Affiliation(s)
| | - Magdalena Mock
- Department of Solar MaterialsLeipzigGermany
- Present address:
Department of Mechanical Engineering and Material SciencesGeorg Agricola University of Applied SciencesBochumGermany
| | | | - Bruno Bühler
- Department of Solar MaterialsLeipzigGermany
- Department of Microbial BiotechnologyHelmholtz Centre for Environmental Research GmbH–UFZLeipzigGermany
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da Camara N, Dubery IA, Piater LA. Proteome Analysis of Nicotiana tabacum Cells following Isonitrosoacetophenone Treatment Reveals Defence-Related Responses Associated with Priming. PLANTS (BASEL, SWITZERLAND) 2023; 12:1137. [PMID: 36903995 PMCID: PMC10005295 DOI: 10.3390/plants12051137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/25/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
Proteins play an essential regulatory role in the innate immune response of host plants following elicitation by either biotic or abiotic stresses. Isonitrosoacetophenone (INAP), an unusual oxime-containing stress metabolite, has been investigated as a chemical inducer of plant defence responses. Both transcriptomic and metabolomic studies of various INAP-treated plant systems have provided substantial insight into this compound's defence-inducing and priming capabilities. To complement previous 'omics' work in this regard, a proteomic approach of time-dependent responses to INAP was followed. As such, Nicotiana tabacum (N. tabacum) cell suspensions were induced with INAP and changes monitored over a 24-h period. Protein isolation and proteome analysis at 0, 8, 16 and 24 h post-treatment were performed using two-dimensional electrophoresis followed by the gel-free eight-plex isobaric tags for relative and absolute quantitation (iTRAQ) based on liquid chromatography and mass spectrometry. Of the identified differentially abundant proteins, 125 were determined to be significant and further investigated. INAP treatment elicited changes to the proteome that affected proteins from a wide range of functional categories: defence, biosynthesis, transport, DNA and transcription, metabolism and energy, translation and signalling and response regulation. The possible roles of the differentially synthesised proteins in these functional classes are discussed. Results indicate up-regulated defence-related activity within the investigated time period, further highlighting a role for proteomic changes in priming as induced by INAP treatment.
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Medić AB, Karadžić IM. Pseudomonas in environmental bioremediation of hydrocarbons and phenolic compounds- key catabolic degradation enzymes and new analytical platforms for comprehensive investigation. World J Microbiol Biotechnol 2022; 38:165. [PMID: 35861883 DOI: 10.1007/s11274-022-03349-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/26/2022] [Indexed: 10/17/2022]
Abstract
Pollution of the environment with petroleum hydrocarbons and phenolic compounds is one of the biggest problems in the age of industrialization and high technology. Species of the genus Pseudomonas, present in almost all hydrocarbon-contaminated areas, play a particular role in biodegradation of these xenobiotics, as the genus has the potential to decompose various hydrocarbons and phenolic compounds, using them as its only source of carbon. Plasticity of carbon metabolism is one of the adaptive strategies used by Pseudomonas to survive exposure to toxic organic compounds, so a good knowledge of its mechanisms of degradation enables the development of new strategies for the treatment of pollutants in the environment. The capacity of microorganisms to metabolize aromatic compounds has contributed to the evolutionally conserved oxygenases. Regardless of the differences in structure and complexity between mono- and polycyclic aromatic hydrocarbons, all these compounds are thermodynamically stable and chemically inert, so for their decomposition, ring activation by oxygenases is crucial. Genus Pseudomonas uses several upper and lower metabolic pathways to transform and degrade hydrocarbons, phenolic compounds, and petroleum hydrocarbons. Data obtained from newly developed omics analytical platforms have enormous potential not only to facilitate our understanding of processes at the molecular level but also enable us to instigate and monitor complex biodegradations by Pseudomonas. Biotechnological application of aromatic metabolic pathways in Pseudomonas to bioremediation of environments polluted with crude oil, biovalorization of lignin for production of bioplastics, biofuel, and bio-based chemicals, as well as Pseudomonas-assisted phytoremediation are also considered.
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Affiliation(s)
- Ana B Medić
- University of Belgrade, Faculty of Medicine, Department of Chemistry, Belgrade, Serbia.
| | - Ivanka M Karadžić
- University of Belgrade, Faculty of Medicine, Department of Chemistry, Belgrade, Serbia
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Extracellular degradation of a polyurethane oligomer involving outer membrane vesicles and further insights on the degradation of 2,4-diaminotoluene in Pseudomonas capeferrum TDA1. Sci Rep 2022; 12:2666. [PMID: 35177693 PMCID: PMC8854710 DOI: 10.1038/s41598-022-06558-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/02/2022] [Indexed: 11/16/2022] Open
Abstract
The continuing reports of plastic pollution in various ecosystems highlight the threat posed by the ever-increasing consumption of synthetic polymers. Therefore, Pseudomonas capeferrum TDA1, a strain recently isolated from a plastic dump site, was examined further regarding its ability to degrade polyurethane (PU) compounds. The previously reported degradation pathway for 2,4-toluene diamine, a precursor and degradation intermediate of PU, could be confirmed by RNA-seq in this organism. In addition, different cell fractions of cells grown on a PU oligomer were tested for extracellular hydrolytic activity using a standard assay. Strikingly, purified outer membrane vesicles (OMV) of P. capeferrum TDA1 grown on a PU oligomer showed higher esterase activity than cell pellets. Hydrolases in the OMV fraction possibly involved in extracellular PU degradation were identified by mass spectrometry. On this basis, we propose a model for extracellular degradation of polyester-based PUs by P. capeferrum TDA1 involving the role of OMVs in synthetic polymer degradation.
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Ray S, Da Costa R, Thakur S, Nandi D. Salmonella Typhimurium encoded cold shock protein E is essential for motility and biofilm formation. MICROBIOLOGY-SGM 2021; 166:460-473. [PMID: 32159509 DOI: 10.1099/mic.0.000900] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ability of bacteria to form biofilms increases their survival under adverse environmental conditions. Biofilms have enormous medical and environmental impact; consequently, the factors that influence biofilm formation are an important area of study. In this investigation, the roles of two cold shock proteins (CSP) during biofilm formation were investigated in Salmonella Typhimurium, which is a major foodborne pathogen. Among all CSP transcripts studied, the expression of cspE (STM14_0732) was higher during biofilm growth. The cspE deletion strain (ΔcspE) did not form biofilms on a cholesterol coated glass surface; however, complementation with WT cspE, but not the F30V mutant, was able to rescue this phenotype. Transcript levels of other CSPs demonstrated up-regulation of cspA (STM14_4399) in ΔcspE. The cspA deletion strain (ΔcspA) did not affect biofilm formation; however, ΔcspEΔcspA exhibited higher biofilm formation compared to ΔcspE. Most likely, the higher cspA amounts in ΔcspE reduced biofilm formation, which was corroborated using cspA over-expression studies. Further functional studies revealed that ΔcspE and ΔcspEΔcspA exhibited slow swimming but no swarming motility. Although cspA over-expression did not affect motility, cspE complementation restored the swarming motility of ΔcspE. The transcript levels of the major genes involved in motility in ΔcspE demonstrated lower expression of the class III (fliC, motA, cheY), but not class I (flhD) or class II (fliA, fliL), flagellar regulon genes. Overall, this study has identified the interplay of two CSPs in regulating two biological processes: CspE is essential for motility in a CspA-independent manner whereas biofilm formation is CspA-dependent.
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Affiliation(s)
- Semanti Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
| | - Rochelle Da Costa
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
| | - Samriddhi Thakur
- Department of Undergraduate Studies, Indian Insitute of Science, Bangalore-560012, India
| | - Dipankar Nandi
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
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Schalck T, den Bergh BV, Michiels J. Increasing Solvent Tolerance to Improve Microbial Production of Alcohols, Terpenoids and Aromatics. Microorganisms 2021; 9:249. [PMID: 33530454 PMCID: PMC7912173 DOI: 10.3390/microorganisms9020249] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/14/2021] [Accepted: 01/20/2021] [Indexed: 12/16/2022] Open
Abstract
Fuels and polymer precursors are widely used in daily life and in many industrial processes. Although these compounds are mainly derived from petrol, bacteria and yeast can produce them in an environment-friendly way. However, these molecules exhibit toxic solvent properties and reduce cell viability of the microbial producer which inevitably impedes high product titers. Hence, studying how product accumulation affects microbes and understanding how microbial adaptive responses counteract these harmful defects helps to maximize yields. Here, we specifically focus on the mode of toxicity of industry-relevant alcohols, terpenoids and aromatics and the associated stress-response mechanisms, encountered in several relevant bacterial and yeast producers. In practice, integrating heterologous defense mechanisms, overexpressing native stress responses or triggering multiple protection pathways by modifying the transcription machinery or small RNAs (sRNAs) are suitable strategies to improve solvent tolerance. Therefore, tolerance engineering, in combination with metabolic pathway optimization, shows high potential in developing superior microbial producers.
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Affiliation(s)
- Thomas Schalck
- VIB Center for Microbiology, Flanders Institute for Biotechnology, B-3001 Leuven, Belgium; (T.S.); (B.V.d.B.)
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
| | - Bram Van den Bergh
- VIB Center for Microbiology, Flanders Institute for Biotechnology, B-3001 Leuven, Belgium; (T.S.); (B.V.d.B.)
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
| | - Jan Michiels
- VIB Center for Microbiology, Flanders Institute for Biotechnology, B-3001 Leuven, Belgium; (T.S.); (B.V.d.B.)
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
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9
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Lyratzakis A, Valsamidis G, Kanavaki I, Nikolaki A, Rupprecht F, Langer JD, Tsiotis G. Proteomic Characterization of the Pseudomonas sp. Strain phDV1 Response to Monocyclic Aromatic Compounds. Proteomics 2020; 21:e2000003. [PMID: 33108051 DOI: 10.1002/pmic.202000003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 10/13/2020] [Indexed: 11/06/2022]
Abstract
The degradation of aromatic compounds comprises an important step in the removal of pollutants and re-utilization of plastics and other non-biological polymers. Here, Pseudomonas sp. strain phDV1, a gram-negative bacterium that is selected for its ability to degrade aromatic compounds is studied. In order to understand how the aromatic compounds and their degradation products are reintroduced in the metabolism of the bacteria and the systematic/metabolic response of the bacterium to the new carbon source, the proteome of this strain is analyzed in the presence of succinate, phenol, and o-, m-, and p-cresol as the sole carbon source. As a reference proteome, the bacteria are grown in succinate and then compared with the respective proteomes of bacteria grown on phenol and different cresols. In total, 2295 proteins are identified; 1908 proteins are used for quantification between different growth conditions. The carbon source affects the synthesis of enzymes related to aromatic compound degradation and in particular the enzyme involved in the meta-pathway of monocyclic aromatic compounds degradation. In addition, proteins involved in the production of polyhydroxyalkanoate (PHA), an attractive biomaterial, show higher abundance in the presence of monocyclic aromatic compounds. The results provide, for the first time, comprehensive information on the proteome response of this strain to monocyclic aromatic compounds.
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Affiliation(s)
- Alexandros Lyratzakis
- Division of Biochemistry, Department of Chemistry, University of Crete, Voutes, Heraklion, GR-71003, Greece
| | - Giannis Valsamidis
- Division of Biochemistry, Department of Chemistry, University of Crete, Voutes, Heraklion, GR-71003, Greece
| | - Iliana Kanavaki
- Division of Biochemistry, Department of Chemistry, University of Crete, Voutes, Heraklion, GR-71003, Greece
| | - Antigoni Nikolaki
- Division of Biochemistry, Department of Chemistry, University of Crete, Voutes, Heraklion, GR-71003, Greece
| | - Fiona Rupprecht
- Max Planck Institute for Brain Research, Max-von-Laue-Straße 4, Frankfurt am Main, D-60438, Germany.,Max Planck Institute for Biophysics, Max-von-Laue-Straße 3, Frankfurt am Main, D-60438, Germany
| | - Julian D Langer
- Max Planck Institute for Brain Research, Max-von-Laue-Straße 4, Frankfurt am Main, D-60438, Germany.,Max Planck Institute for Biophysics, Max-von-Laue-Straße 3, Frankfurt am Main, D-60438, Germany
| | - Georgios Tsiotis
- Division of Biochemistry, Department of Chemistry, University of Crete, Voutes, Heraklion, GR-71003, Greece
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Xu G, Xiao L, Wu A, Han R, Ni Y. Enhancing n-Butanol Tolerance of Escherichia coli by Overexpressing of Stress-Responsive Molecular Chaperones. Appl Biochem Biotechnol 2020; 193:257-270. [PMID: 32929579 DOI: 10.1007/s12010-020-03417-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/23/2020] [Indexed: 12/14/2022]
Abstract
Microbial tolerance to organic solvents is critical for efficient production of biofuels. In this study, n-butanol tolerance of Escherichia coli JM109 was improved by overexpressing of genes encoding stress-responsive small RNA-regulator, RNA chaperone, and molecular chaperone. Gene rpoS, coding for sigma S subunit of RNA polymerase, was the most efficient in improving n-butanol tolerance of E. coli. The highest OD600 and the specific growth rate of JM109/pQE80L-rpoS reached 1.692 and 0.144 h-1 respectively at 1.0% (v/v) n-butanol. Double and triple expression of molecular chaperones rpoS, secB, and groS were conducted and optimized. Recombinant strains JM109/pQE80L-secB-rpoS and JM109/pQE80L-groS-secB-rpoS exhibited the highest n-butanol tolerance, with specific growth rates of 0.164 and 0.165 h-1, respectively. Membrane integrity, potentials, and cell morphology analyses demonstrated the high viability of JM109/pQE80L-groS-secB-rpoS. This study provides guidance on employing various molecular chaperones for enhancing the tolerance of E. coli against n-butanol.
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Affiliation(s)
- Guochao Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Lin Xiao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Anning Wu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Ruizhi Han
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Ye Ni
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China.
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Systems Analysis of NADH Dehydrogenase Mutants Reveals Flexibility and Limits of Pseudomonas taiwanensis VLB120's Metabolism. Appl Environ Microbiol 2020; 86:AEM.03038-19. [PMID: 32245760 DOI: 10.1128/aem.03038-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/18/2020] [Indexed: 12/14/2022] Open
Abstract
Obligate aerobic organisms rely on a functional electron transport chain for energy conservation and NADH oxidation. Because of this essential requirement, the genes of this pathway are likely constitutively and highly expressed to avoid a cofactor imbalance and energy shortage under fluctuating environmental conditions. We here investigated the essentiality of the three NADH dehydrogenases of the respiratory chain of the obligate aerobe Pseudomonas taiwanensis VLB120 and the impact of the knockouts of corresponding genes on its physiology and metabolism. While a mutant lacking all three NADH dehydrogenases seemed to be nonviable, the single or double knockout mutant strains displayed no, or only a weak, phenotype. Only the mutant deficient in both type 2 dehydrogenases showed a clear phenotype with biphasic growth behavior and a strongly reduced growth rate in the second phase. In-depth analyses of the metabolism of the generated mutants, including quantitative physiological experiments, transcript analysis, proteomics, and enzyme activity assays revealed distinct responses to type 2 and type 1 dehydrogenase deletions. An overall high metabolic flexibility enables P. taiwanensis to cope with the introduced genetic perturbations and maintain stable phenotypes, likely by rerouting of metabolic fluxes. This metabolic adaptability has implications for biotechnological applications. While the phenotypic robustness is favorable in large-scale applications with inhomogeneous conditions, the possible versatile redirecting of carbon fluxes upon genetic interventions can thwart metabolic engineering efforts.IMPORTANCE While Pseudomonas has the capability for high metabolic activity and the provision of reduced redox cofactors important for biocatalytic applications, exploitation of this characteristic might be hindered by high, constitutive activity of and, consequently, competition with the NADH dehydrogenases of the respiratory chain. The in-depth analysis of NADH dehydrogenase mutants of Pseudomonas taiwanensis VLB120 presented here provides insight into the phenotypic and metabolic response of this strain to these redox metabolism perturbations. This high degree of metabolic flexibility needs to be taken into account for rational engineering of this promising biotechnological workhorse toward a host with a controlled and efficient supply of redox cofactors for product synthesis.
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12
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Stress-tolerant non-conventional microbes enable next-generation chemical biosynthesis. Nat Chem Biol 2020; 16:113-121. [DOI: 10.1038/s41589-019-0452-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022]
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13
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Smułek W, Zdarta A, Pacholak A, Runka T, Kaczorek E. Increased biological removal of 1-chloronaphthalene as a result of exposure: A study of bacterial adaptation strategies. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 185:109707. [PMID: 31561078 DOI: 10.1016/j.ecoenv.2019.109707] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 09/12/2019] [Accepted: 09/20/2019] [Indexed: 06/10/2023]
Abstract
Effective biodegradation of hydrophobic pollutants, such as 1-chloronaphthalene, is strictly associated with the adaptation of environmental bacteria to their assimilation. This study explores the relation between the modifications of cell properties of bacteria belonging to Pseudomonas and Serratia genera resulting from a 12-month exposure to 1-chloronaphthalene, and their biodegradation efficiency. In the presented study, both bacterial strains exhibited higher (70%) degradation of this compound after exposure compared to unexposed (55%) systems. This adaptation can be associated with increased ratio of polysaccharides in the outer layers of bacterial cells, which was confirmed using infrared spectroscopy analysis. Additionally, the analysis of Raman spectra indicated conformational changes of extracellular carbohydrates from α- to β-anomeric structure. Moreover, the changes in the cell surface hydrophobicity and cell membrane permeability differed between the strains and the Pseudomonas strain exhibited more significant modifications of these parameters. The results suggest that adaptation strategies of both tested strains are different and involve diverse reconstructions of the cell wall and membranes. The results provide a novel and deep insight into the interactions between environmental bacterial strains and chloroaromatic compounds, which opens new perspectives for applying spectrometric methods in investigation of cell adaptation strategies as a result of long-term contact with toxic pollutants.
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Affiliation(s)
- Wojciech Smułek
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965, Poznań, Poland.
| | - Agata Zdarta
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965, Poznań, Poland
| | - Amanda Pacholak
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965, Poznań, Poland
| | - Tomasz Runka
- Institute of Materials Research and Quantum Engineering, Poznan University of Technology, Piotrowo 3, 60-965, Poznań, Poland
| | - Ewa Kaczorek
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965, Poznań, Poland
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14
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Volmer J, Lindmeyer M, Seipp J, Schmid A, Bühler B. Constitutively solvent‐tolerantPseudomonas taiwanensisVLB120∆C∆ttgVsupports particularly high‐styrene epoxidation activities when grown under glucose excess conditions. Biotechnol Bioeng 2019; 116:1089-1101. [DOI: 10.1002/bit.26924] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/17/2018] [Accepted: 01/06/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Jan Volmer
- Department of Biochemical and Chemical EngineeringTU Dortmund UniversityDortmund Germany
| | - Martin Lindmeyer
- Department of Biochemical and Chemical EngineeringTU Dortmund UniversityDortmund Germany
- Department of Solar MaterialsHelmholtz Centre for Environmental Research GmbH–UFZLeipzig Germany
| | - Julia Seipp
- Department of Biochemical and Chemical EngineeringTU Dortmund UniversityDortmund Germany
| | - Andreas Schmid
- Department of Solar MaterialsHelmholtz Centre for Environmental Research GmbH–UFZLeipzig Germany
| | - Bruno Bühler
- Department of Solar MaterialsHelmholtz Centre for Environmental Research GmbH–UFZLeipzig Germany
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15
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Kuang S, Fan X, Peng R. Quantitative proteomic analysis ofRhodococcus ruberresponsive to organic solvents. BIOTECHNOL BIOTEC EQ 2018. [DOI: 10.1080/13102818.2018.1533432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Sufang Kuang
- Department of Bioengineering, College of Life Science, Jiangxi Normal University, Nanchang, PR China
| | - Xin Fan
- Department of Bioengineering, College of Life Science, Jiangxi Normal University, Nanchang, PR China
| | - Ren Peng
- Department of Bioengineering, College of Life Science, Jiangxi Normal University, Nanchang, PR China
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16
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Solvent Tolerance in Bacteria: Fulfilling the Promise of the Biotech Era? Trends Biotechnol 2018; 36:1025-1039. [DOI: 10.1016/j.tibtech.2018.04.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/17/2018] [Accepted: 04/19/2018] [Indexed: 01/01/2023]
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17
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Zdarta A, Tracz J, Luczak M, Guzik U, Kaczorek E. Hydrocarbon-induced changes in proteins and fatty acids profiles of Raoultella ornithinolytica M03. J Proteomics 2017; 164:43-51. [DOI: 10.1016/j.jprot.2017.05.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/25/2017] [Accepted: 05/31/2017] [Indexed: 01/04/2023]
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18
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Fiedurek J, Trytek M, Szczodrak J. Strain improvement of industrially important microorganisms based on resistance to toxic metabolites and abiotic stress. J Basic Microbiol 2017; 57:445-459. [DOI: 10.1002/jobm.201600710] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/04/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Jan Fiedurek
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
| | - Mariusz Trytek
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
| | - Janusz Szczodrak
- Department of Industrial Microbiology; Institute of Microbiology and Biotechnology; Maria Curie-Skłodowska University; Lublin Poland
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19
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Molina-Santiago C, Udaondo Z, Gómez-Lozano M, Molin S, Ramos JL. Global transcriptional response of solvent-sensitive and solvent-tolerant Pseudomonas putida strains exposed to toluene. Environ Microbiol 2016; 19:645-658. [PMID: 27768818 DOI: 10.1111/1462-2920.13585] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 10/17/2016] [Indexed: 12/23/2022]
Abstract
Pseudomonas putida strains are generally recognized as solvent tolerant, exhibiting varied sensitivity to organic solvents. Pan-genome analysis has revealed that 30% of genes belong to the core-genome of Pseudomonas. Accessory and unique genes confer high degree of adaptability and capabilities for the degradation and synthesis of a wide range of chemicals. For the use of these microbes in bioremediation and biocatalysis, it is critical to understand the mechanisms underlying these phenotypic differences. In this study, RNA-seq analysis compared the short- and long-term responses of the toluene-sensitive KT2440 strain and the highly tolerant DOT-T1E strain. The sensitive strain activates a larger number of genes in a higher magnitude than DOT-T1E. This is expected because KT2440 bears one toluene tolerant pump, while DOT-T1E encodes three of these pumps. Both strains activate membrane modifications to reduce toluene membrane permeability. The KT2440 strain activates the TCA cycle to generate energy, while avoiding energy-intensive processes such as flagellar biosynthesis. This suggests that KT2440 responds to toluene by focusing on survival mechanisms. The DOT-T1E strain activates toluene degradation pathways, using toluene as source of energy. Among the unique genes encoded by DOT-T1E is a 70 kb island composed of genes of unknown function induced in response to toluene.
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Affiliation(s)
- Carlos Molina-Santiago
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, C/Profesor Albareda 1, Granada, E-18008, Spain
| | - Zulema Udaondo
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, C/Profesor Albareda 1, Granada, E-18008, Spain
| | - María Gómez-Lozano
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Soren Molin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Juan-Luis Ramos
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, C/Profesor Albareda 1, Granada, E-18008, Spain
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20
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Poblete-Castro I, Borrero-de Acuña JM, Nikel PI, Kohlstedt M, Wittmann C. Host Organism: Pseudomonas putida. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807796.ch8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Ignacio Poblete-Castro
- Universidad Andrés Bello; Center for Bioinformatics and Integrative Biology, Biosystems Engineering Laboratory, Faculty of Biological Sciences; Av. República 239 8340176 Santiago de Chile Chile
| | - José M. Borrero-de Acuña
- Universidad Andrés Bello; Center for Bioinformatics and Integrative Biology, Biosystems Engineering Laboratory, Faculty of Biological Sciences; Av. República 239 8340176 Santiago de Chile Chile
| | - Pablo I. Nikel
- Systems and Synthetic Biology Program; National Spanish Center for Biotechnology (CNB-CSIC); Calle Darwin, 3 28049 Madrid, Spain
| | - Michael Kohlstedt
- Saarland University; Institute of Systems Biology, Biosciences; Campus A1.5 66123 Saarbrücken, Germany
| | - Christoph Wittmann
- Saarland University; Institute of Systems Biology, Biosciences; Campus A1.5 66123 Saarbrücken, Germany
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21
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Kundu D, Hazra C, Chaudhari A. Biodegradation of 2,6-dinitrotoluene and plant growth promoting traits by Rhodococcus pyridinivorans NT2: Identification and toxicological analysis of metabolites and proteomic insights. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2016. [DOI: 10.1016/j.bcab.2016.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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22
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Sayqal A, Xu Y, Trivedi DK, AlMasoud N, Ellis DI, Rattray NJW, Goodacre R. Metabolomics Analysis Reveals the Participation of Efflux Pumps and Ornithine in the Response of Pseudomonas putida DOT-T1E Cells to Challenge with Propranolol. PLoS One 2016; 11:e0156509. [PMID: 27331395 PMCID: PMC4917112 DOI: 10.1371/journal.pone.0156509] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/16/2016] [Indexed: 02/07/2023] Open
Abstract
Efflux pumps are critically important membrane components that play a crucial role in strain tolerance in Pseudomonas putida to antibiotics and aromatic hydrocarbons that result in these toxicants being expelled from the bacteria. Here, the effect of propranolol on P. putida was examined by sudden addition of 0.2, 0.4 and 0.6 mg mL-1 of this β-blocker to several strains of P. putida, including the wild type DOT-T1E and the efflux pump knockout mutants DOT-T1E-PS28 and DOT-T1E-18. Bacterial viability measurements reveal that the efflux pump TtgABC plays a more important role than the TtgGHI pump in strain tolerance to propranolol. Mid-infrared (MIR) spectroscopy was then used as a rapid, high-throughput screening tool to investigate any phenotypic changes resulting from exposure to varying levels of propranolol. Multivariate statistical analysis of these MIR data revealed gradient trends in resultant ordination scores plots, which were related to the concentration of propranolol. MIR illustrated phenotypic changes associated with the presence of this drug within the cell that could be assigned to significant changes that occurred within the bacterial protein components. To complement this phenotypic fingerprinting approach metabolic profiling was performed using gas chromatography mass spectrometry (GC-MS) to identify metabolites of interest during the growth of bacteria following toxic perturbation with the same concentration levels of propranolol. Metabolic profiling revealed that ornithine, which was only produced by P. putida cells in the presence of propranolol, presents itself as a major metabolic feature that has important functions in propranolol stress tolerance mechanisms within this highly significant and environmentally relevant species of bacteria.
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Affiliation(s)
- Ali Sayqal
- Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Yun Xu
- Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Drupad K. Trivedi
- Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Najla AlMasoud
- Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - David I. Ellis
- Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Nicholas J. W. Rattray
- Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Royston Goodacre
- Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
- * E-mail:
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23
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Yang JW, Zheng DJ, Cui BD, Yang M, Chen YZ. RNA-seq transcriptome analysis of a Pseudomonas strain with diversified catalytic properties growth under different culture medium. Microbiologyopen 2016; 5:626-36. [PMID: 27061463 PMCID: PMC4985596 DOI: 10.1002/mbo3.357] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/23/2016] [Accepted: 03/03/2016] [Indexed: 11/11/2022] Open
Abstract
Biocatalysis is an emerging strategy for the production of enantio-pure organic molecules. However, lacking of commercially available enzymes restricts the widespread application of biocatalysis. In this study, we report a Pseudomonas strain which exhibited versatile oxidation activity to synthesize chiral sulfoxides when growing under M9-toluene medium and reduction activity to synthesize chiral alcohols when on Luria-Bertani (LB) medium, respectively. Further comparative transcriptome analysis on samples from these two cultural conditions has identified 1038 differentially expressed genes (DEG). Gene Ontology (GO) enrichment and KEGG pathways analysis demonstrate significant changes in protein synthesis, energy metabolism, and biosynthesis of metabolites when cells cultured under different conditions. We have identified eight candidate enzymes from this bacterial which may have the potential to be used for synthesis of chiral alcohol and sulfoxide chemicals. This work provides insights into the mechanism of diversity in catalytic properties of this Pseudomonas strain growth with different cultural conditions, as well as candidate enzymes for further biocatalysis of enantiomerically pure molecules and pharmaceuticals.
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Affiliation(s)
- Jia-Wei Yang
- Department of Biochemistry, Zunyi Medical University, Zunyi, 563003, China
| | - Dai-Jun Zheng
- School of Pharmacy, Zunyi Medical University, Zunyi, 563000, China
| | - Bao-Dong Cui
- Department of Biochemistry, Zunyi Medical University, Zunyi, 563003, China
| | - Min Yang
- School of Pharmacy, Zunyi Medical University, Zunyi, 563000, China
| | - Yong-Zheng Chen
- School of Pharmacy, Zunyi Medical University, Zunyi, 563000, China
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24
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Michael E, Nitzan Y, Langzam Y, Luboshits G, Cahan R. Effect of toluene on Pseudomonas stutzeri ST-9 morphology - plasmolysis, cell size, and formation of outer membrane vesicles. Can J Microbiol 2016; 62:682-91. [PMID: 27256870 DOI: 10.1139/cjm-2016-0099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isolated toluene-degrading Pseudomonas stutzeri ST-9 bacteria were grown in a minimal medium containing toluene (100 mg·L(-1)) (MMT) or glucose (MMG) as the sole carbon source, with specific growth rates of 0.019 h(-1) and 0.042 h(-1), respectively. Scanning (SEM) as well as transmission (TEM) electron microscope analyses showed that the bacterial cells grown to mid-log phase in the presence of toluene possess a plasmolysis space. TEM analysis revealed that bacterial cells that were grown in MMT were surrounded by an additional "material" with small vesicles in between. Membrane integrity was analyzed by leakage of 260 nm absorbing material and demonstrated only 7% and 8% leakage from cultures grown in MMT compared with MMG. X-ray microanalysis showed a 4.3-fold increase in Mg and a 3-fold increase in P in cells grown in MMT compared with cells grown in MMG. Fluorescence-activated cell sorting (FACS) analysis indicated that the permeability of the membrane to propidium iodide was 12.6% and 19.6% when the cultures were grown in MMG and MMT, respectively. The bacterial cell length increased by 8.5% ± 0.1% and 17% ± 2%, as measured using SEM images and FACS analysis, respectively. The results obtained in this research show that the presence of toluene led to morphology changes, such as plasmolysis, cell size, and formation of outer membrane vesicles. However, it does not cause significant damage to membrane integrity.
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Affiliation(s)
- Esti Michael
- a Department of Chemical Engineering, Ariel University, Ariel 40700, Israel.,b The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Yeshayahu Nitzan
- b The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Yakov Langzam
- b The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Galia Luboshits
- a Department of Chemical Engineering, Ariel University, Ariel 40700, Israel
| | - Rivka Cahan
- a Department of Chemical Engineering, Ariel University, Ariel 40700, Israel
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25
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Currie F, Broadhurst DI, Dunn WB, Sellick CA, Goodacre R. Metabolomics reveals the physiological response of Pseudomonas putida KT2440 (UWC1) after pharmaceutical exposure. MOLECULAR BIOSYSTEMS 2016; 12:1367-77. [PMID: 26932201 DOI: 10.1039/c5mb00889a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human pharmaceuticals have been detected in wastewater treatment plants, rivers, and estuaries throughout Europe and the United States. It is widely acknowledged that there is insufficient information available to determine whether prolonged exposure to low levels of these substances is having an impact on the microbial ecology in such environments. In this study we attempt to measure the effects of exposing cultures of Pseudomonas putida KT2440 (UWC1) to six pharmaceuticals by looking at differences in metabolite levels. Initially, we used Fourier transform infrared (FT-IR) spectroscopy coupled with multivariate analysis to discriminate between cell cultures exposed to different pharmaceuticals. This suggested that on exposure to propranolol there were significant changes in the lipid complement of P. putida. Metabolic profiling with gas chromatography-mass spectrometry (GC-MS), coupled with univariate statistical analyses, was used to identify endogenous metabolites contributing to discrimination between cells exposed to the six drugs. This approach suggested that the energy reserves of exposed cells were being expended and was particularly evident on exposure to propranolol. Adenosine triphosphate (ATP) concentrations were raised in P. putida exposed to propranolol. Increased energy requirements may be due to energy dependent efflux pumps being used to remove propranolol from the cell.
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Affiliation(s)
- Felicity Currie
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7ND, UK.
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26
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Espinosa-Urgel M, Serrano L, Ramos JL, Fernández-Escamilla AM. Engineering Biological Approaches for Detection of Toxic Compounds: A New Microbial Biosensor Based on the Pseudomonas putida TtgR Repressor. Mol Biotechnol 2016; 57:558-64. [PMID: 25731724 DOI: 10.1007/s12033-015-9849-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Environmental contamination by toxic organic compounds and antimicrobials is one of the causes for the recent surge of multidrug-resistant pathogenic bacteria. Monitoring contamination is therefore the first step in containment of antimicrobial resistance and requires the development of simple, sensitive, and quantitative tools that detect a broad spectrum of toxic compounds. In this study, we have engineered a new microbial biosensor based on the ttgR-regulated promoter that controls expression of the TtgABC extrusion efflux pump of Pseudomonas putida, coupled to a gfp reporter. The system was introduced in P. putida DOT-T1E, a strain characterized by its ability to survive in the presence of high concentrations of diverse toxic organic compounds. This whole-cell biosensor is capable to detect a wide range of structurally diverse antibiotics, as well as compounds such as toluene or flavonoids.
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Affiliation(s)
- Manuel Espinosa-Urgel
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), C/Profesor Albareda, 1, 18008, Granada, Spain
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27
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Sayqal A, Xu Y, Trivedi DK, AlMasoud N, Ellis DI, Muhamadali H, Rattray NJW, Webb C, Goodacre R. Metabolic analysis of the response of Pseudomonas putida DOT-T1E strains to toluene using Fourier transform infrared spectroscopy and gas chromatography mass spectrometry. Metabolomics 2016; 12:112. [PMID: 27398079 PMCID: PMC4916193 DOI: 10.1007/s11306-016-1054-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/04/2016] [Indexed: 01/09/2023]
Abstract
INTRODUCTION An exceptionally interesting stress response of Pseudomonas putida strains to toxic substances is the induction of efflux pumps that remove toxic chemical substances from the bacterial cell out to the external environment. To exploit these microorganisms to their full potential a deeper understanding of the interactions between the bacteria and organic solvents is required. Thus, this study focuses on investigation of metabolic changes in P. putida upon exposure to toluene. OBJECTIVE Investigate observable metabolic alterations during interactions of three strains of P. putida (DOT-T1E, and its mutants DOT-T1E-PS28 and DOT-T1E-18) with the aromatic hydrocarbon toluene. METHODS The growth profiles were measured by taking optical density (OD) measurement at 660 nm (OD660) at various time points during incubation. For fingerprinting analysis, Fourier-transform infrared (FT-IR) spectroscopy was used to investigate any phenotypic changes resulting from exposure to toluene. Metabolic profiling analysis was performed using gas chromatography-mass spectrometry (GC-MS). Principal component-discriminant function analysis (PC-DFA) was applied to the FT-IR data while multiblock principal component analysis (MB-PCA) and N-way analysis of variance (N-way ANOVA) were applied to the GC-MS data. RESULTS The growth profiles demonstrated the effect of toluene on bacterial cultures and the results suggest that the mutant P. putida DOT-T1E-18 was more sensitive (significantly affected) to toluene compared to the other two strains. PC-DFA on FT-IR data demonstrated the differentiation between different conditions of toluene on bacterial cells, which indicated phenotypic changes associated with the presence of the solvent within the cell. Fifteen metabolites associated with this phenotypic change, in P. putida due to exposure to solvent, were from central metabolic pathways. Investigation of MB-PCA loading plots and N-way ANOVA for condition | strain × time blocking (dosage of toluene) suggested ornithine as the most significant compound that increased upon solvent exposure. CONCLUSION The combination of metabolic fingerprinting and profiling with suitable multivariate analysis revealed some interesting leads for understanding the mechanism of Pseudomonas strains response to organic solvent exposure.
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Affiliation(s)
- Ali Sayqal
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
| | - Yun Xu
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
| | - Drupad K. Trivedi
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
| | - Najla AlMasoud
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
| | - David I. Ellis
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
| | - Howbeer Muhamadali
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
| | - Nicholas J. W. Rattray
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
| | - Carole Webb
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
| | - Royston Goodacre
- School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN UK
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Bhaganna P, Bielecka A, Molinari G, Hallsworth JE. Protective role of glycerol against benzene stress: insights from the Pseudomonas putida proteome. Curr Genet 2015; 62:419-29. [PMID: 26612269 DOI: 10.1007/s00294-015-0539-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 11/04/2015] [Accepted: 11/05/2015] [Indexed: 01/09/2023]
Abstract
Chemical activities of hydrophobic substances can determine the windows of environmental conditions over which microbial systems function and the metabolic inhibition of microorganisms by benzene and other hydrophobes can, paradoxically, be reduced by compounds that protect against cellular water stress (Bhaganna et al. in Microb Biotechnol 3:701-716, 2010; Cray et al. in Curr Opin Biotechnol 33:228-259, 2015a). We hypothesized that this protective effect operates at the macromolecule structure-function level and is facilitated, in part at least, by genome-mediated adaptations. Based on proteome profiling of the soil bacterium Pseudomonas putida, we present evidence that (1) benzene induces a chaotrope-stress response, whereas (2) cells cultured in media supplemented with benzene plus glycerol were protected against chaotrope stress. Chaotrope-stress response proteins, such as those involved in lipid and compatible-solute metabolism and removal of reactive oxygen species, were increased by up to 15-fold in benzene-stressed cells relative to those of control cultures (no benzene added). By contrast, cells grown in the presence of benzene + glycerol, even though the latter grew more slowly, exhibited only a weak chaotrope-stress response. These findings provide evidence to support the hypothesis that hydrophobic substances induce a chaotropicity-mediated water stress, that cells respond via genome-mediated adaptations, and that glycerol protects the cell's macromolecular systems. We discuss the possibility of using compatible solutes to mitigate hydrocarbon-induced stresses in lignocellulosic biofuel fermentations and for industrial and environmental applications.
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Affiliation(s)
- Prashanth Bhaganna
- MBC, School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, BT9 7BL, Northern Ireland, UK
| | - Agata Bielecka
- Environmental Microbiology Laboratory, Helmholtz Centre for Infection Research, D-38124, Braunschweig, Germany
- Molecular Biology Department, Helmholtz Centre for Infection Research, D-38124, Braunschweig, Germany
| | - Gabriella Molinari
- Environmental Microbiology Laboratory, Helmholtz Centre for Infection Research, D-38124, Braunschweig, Germany
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, D-38124, Braunschweig, Germany
| | - John E Hallsworth
- MBC, School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, BT9 7BL, Northern Ireland, UK.
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29
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Efflux systems in bacteria and their metabolic engineering applications. Appl Microbiol Biotechnol 2015; 99:9381-93. [PMID: 26363557 DOI: 10.1007/s00253-015-6963-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/20/2015] [Accepted: 08/22/2015] [Indexed: 10/23/2022]
Abstract
The production of valuable chemicals from metabolically engineered microbes can be limited by excretion from the cell. Efflux is often overlooked as a bottleneck in metabolic pathways, despite its impact on alleviating feedback inhibition and product toxicity. In the past, it has been assumed that endogenous efflux pumps and membrane porins can accommodate product efflux rates; however, there are an increasing number of examples wherein overexpressing efflux systems is required to improve metabolite production. In this review, we highlight specific examples from the literature where metabolite export has been studied to identify unknown transporters, increase tolerance to metabolites, and improve the production capabilities of engineered bacteria. The review focuses on the export of a broad spectrum of valuable chemicals including amino acids, sugars, flavins, biofuels, and solvents. The combined set of examples supports the hypothesis that efflux systems can be identified and engineered to confer export capabilities on industrially relevant microbes.
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30
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Molecular mechanism involved in the response to hydrogen peroxide stress in Acinetobacter oleivorans DR1. Appl Microbiol Biotechnol 2015; 99:10611-26. [PMID: 26298700 DOI: 10.1007/s00253-015-6914-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/26/2015] [Accepted: 08/03/2015] [Indexed: 10/23/2022]
Abstract
Two-dimensional gel electrophoresis was conducted to investigate the effect of H2O2 on whole protein expression in Acinetobacter oleivorans DR1. Functional classification of 13 upregulated proteins using MALDI-TOF mass spectrometry showed relationships with oxidative stress, energy production and conversion, nucleotide and amino acid metabolism, membrane-related, ion transport, and chaperone-related functions. Alignment of OxyR-binding regions from Pseudomonas aeruginosa and Escherichia coli with promoters of identified proteins revealed that only ahpC, ahpF, and trxB (thioredoxin-disulfide reductase) genes, along with a newly found oprC (putative outer membrane receptor protein) gene, have OxyR-binding sites. The oxyR and ahpC mutants were more sensitive to H2O2 and showed growth defects in both nutritional and n-hexadecane-amended media. Four catalases present in the genome of A. oleivorans DR1 were not detected, which led us to confirm the expression and activity of those catalases in the presence of H2O2. The expression patterns of the four catalase genes differed at different concentrations of H2O2. Interestingly, the promoters of both known OxyR-controlled katG gene (AOLE_17390) and putative small catalase gene (AOLE_09800) have OxyR-binding sites. Gel-shift assay confirmed OxyR binding to the promoter regions of newly identified OxyR-controlled genes encoding OprC and a putative catalase. Hierarchical expression and OxyR-binding of several OxyR-controlled genes suggested that concentration is an important factor in inducing the set of genes under H2O2 stress.
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31
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Vallon T, Simon O, Rendgen-Heugle B, Frana S, Mückschel B, Broicher A, Siemann-Herzberg M, Pfannenstiel J, Hauer B, Huber A, Breuer M, Takors R. Applying systems biology tools to studyn-butanol degradation inPseudomonas putidaKT2440. Eng Life Sci 2015. [DOI: 10.1002/elsc.201400051] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Tobias Vallon
- Institute of Biochemical Engineering; University of Stuttgart; Stuttgart Germany
| | - Oliver Simon
- Proteomics Core Facility of the Life Science Center; University of Hohenheim; Stuttgart Germany
| | - Beate Rendgen-Heugle
- Institute of Biochemical Engineering; University of Stuttgart; Stuttgart Germany
| | - Sabine Frana
- Institute of Biochemical Engineering; University of Stuttgart; Stuttgart Germany
| | - Björn Mückschel
- Institute of Technical Biochemistry; University of Stuttgart; Stuttgart Germany
| | - Alexander Broicher
- Institute of Biochemical Engineering; University of Stuttgart; Stuttgart Germany
| | | | - Jens Pfannenstiel
- Proteomics Core Facility of the Life Science Center; University of Hohenheim; Stuttgart Germany
| | - Bernhard Hauer
- Institute of Technical Biochemistry; University of Stuttgart; Stuttgart Germany
| | - Achim Huber
- Proteomics Core Facility of the Life Science Center; University of Hohenheim; Stuttgart Germany
| | - Michael Breuer
- BASF SE; Fine Chemicals and Biocatalysis Research; Ludwigshafen Germany
| | - Ralf Takors
- Institute of Biochemical Engineering; University of Stuttgart; Stuttgart Germany
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Ramos JL, Sol Cuenca M, Molina-Santiago C, Segura A, Duque E, Gómez-García MR, Udaondo Z, Roca A. Mechanisms of solvent resistance mediated by interplay of cellular factors inPseudomonas putida. FEMS Microbiol Rev 2015; 39:555-66. [DOI: 10.1093/femsre/fuv006] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2015] [Indexed: 11/14/2022] Open
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Analysis of the molecular response of Pseudomonas putida KT2440 to the next-generation biofuel n-butanol. J Proteomics 2015; 122:11-25. [PMID: 25829261 DOI: 10.1016/j.jprot.2015.03.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/25/2015] [Accepted: 03/10/2015] [Indexed: 11/24/2022]
Abstract
UNLABELLED To increase the efficiency of biocatalysts a thorough understanding of the molecular response of the biocatalyst to precursors, products and environmental conditions applied in bioconversions is essential. Here we performed a comprehensive proteome and phospholipid analysis to characterize the molecular response of the potential biocatalyst Pseudomonas putida KT2440 to the next-generation biofuel n-butanol. Using complementary quantitative proteomics approaches we were able to identify and quantify 1467 proteins, corresponding to 28% of the total KT2440 proteome. 256 proteins were altered in abundance in response to n-butanol. The proteome response entailed an increased abundance of enzymes involved in n-butanol degradation including quinoprotein alcohol dehydrogenases, aldehyde dehydrogenases and enzymes of fatty acid beta oxidation. From these results we were able to construct a pathway for the metabolism of n-butanol in P. putida. The initial oxidation of n-butanol is catalyzed by at least two quinoprotein ethanol dehydrogenases (PedE and PedH). Growth of mutants lacking PedE and PedH on n-butanol was significantly impaired, but not completely inhibited, suggesting that additional alcohol dehydrogenases can at least partially complement their function in KT2440. Furthermore, phospholipid profiling revealed a significantly increased abundance of lyso-phospholipids in response to n-butanol, indicating a rearrangement of the lipid bilayer. BIOLOGICAL SIGNIFICANCE n-butanol is an important bulk chemical and a promising alternative to gasoline as a transportation fuel. Due to environmental concerns as well as increasing energy prices there is a growing interest in sustainable and cost-effective biotechnological production processes for the production of bulk chemicals and transportation fuels from renewable resources. n-butanol fermentation is well established in Clostridiae, but the efficiency of n-butanol production is mainly limited by its toxicity. Therefore bacterial strains with higher intrinsic tolerance to n-butanol have to be selected as hosts for n-butanol production. Pseudomonas bacteria are metabolically very versatile and exhibit a high intrinsic tolerance to organic solvents making them suitable candidates for bioconversion processes. A prerequisite for a potential production of n-butanol in Pseudomonas bacteria is a thorough understanding of the molecular adaption processes caused by n-butanol and the identification of enzymes involved in n-butanol metabolization. This work describes the impact of n-butanol on the proteome and the phospholipid composition of the reference strain P. putida KT2440. The high proteome coverage of our proteomics survey allowed us to reconstruct the degradation pathway of n-butanol and to monitor the changes in the energy metabolism of KT2440 induced by n-butanol. Key enzymes involved in n-butanol degradation identified in study will be interesting targets for optimization of n-butanol production in Pseudomonads. The present work and the identification of key enzymes involved in butanol metabolism may serve as a fundament to develop new or improve existing strategies for the biotechnological production of the next-generation biofuel n-butanol in Pseudomonads.
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Li S, Liu L, Chen J. Mitochondrial fusion and fission are involved in stress tolerance of Candida glabrata. BIORESOUR BIOPROCESS 2015. [DOI: 10.1186/s40643-015-0041-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Abstract
Background
Recently, cell tolerance toward environmental stresses has become the major problem in the development of industrial microbial fermentation. Acetoin is an important chemical that can be synthesized by microbes. Its toxicity was investigated using Candida glabrata as the model in this study.
Results
A series of physiological and biochemical experiments demonstrated that the organic solvent acetoin can inhibit cell growth by increasing intracellular reactive oxygen species (ROS) production and inducing damage to mitochondria and cell apoptosis. Integrating RT-PCR experiments, the genes fzo1 and dnm1 were overexpressed to regulate the balance between mitochondrial fusion and fission. Enhancement of mitochondrial fusion was shown to significantly increase cell tolerance toward acetoin stress by inhibiting ROS production and increasing the intracellular adenosine triphosphate (ATP) supply, which was also demonstrated by the addition of citrate.
Conclusions
Regulating mitochondrial fusion-fission may be an alternative strategy for rationally improving the growth performance of eukaryotes under high environmental stress conditions, and also expands our knowledge of the mechanisms of cell tolerance through the processes of energy-related metabolic pathways.
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Baker E, Tang Y, Chu F, Tisa LS. Molecular responses of Frankia sp. strain QA3 to naphthalene. Can J Microbiol 2015; 61:281-92. [PMID: 25742598 DOI: 10.1139/cjm-2014-0786] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Frankia-actinorhizal plant symbiosis plays a significant role in plant colonization in soils contaminated with heavy metals and toxic aromatic hydrocarbons. The molecular response of Frankia upon exposure to soil contaminants is not well understood. To address this issue, we subjected Frankia sp. strain QA3 to naphthalene stress and showed that it could grow on naphthalene as a sole carbon source. Bioinformatic analysis of the Frankia QA3 genome identified a potential operon for aromatic compound degradation as well as several ring-hydroxylating dioxygenases. Under naphthalene stress, the expression of these genes was upregulated. Proteome analysis showed a differential protein profile for cells under naphthalene stress. Several protein spots were analyzed and used to identify proteins involved in stress response, metabolism, and energy production, including a lignostilbene dioxygenase. These results provide a model for understanding the molecular response of Frankia to common soil pollutants, which may be required for survival and proliferation of the bacterium and their hosts in polluted environments.
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Affiliation(s)
- Ethan Baker
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, 46 College Road, Durham, NH 03824-2617, USA
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36
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Mujahid M, Prasuna ML, Sasikala C, Ramana CV. Integrated Metabolomic and Proteomic Analysis Reveals Systemic Responses of Rubrivivax benzoatilyticus JA2 to Aniline Stress. J Proteome Res 2014; 14:711-27. [DOI: 10.1021/pr500725b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Md Mujahid
- Department
of Plant Sciences, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500 046, India
| | - M Lakshmi Prasuna
- Department
of Plant Sciences, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500 046, India
| | - Ch Sasikala
- Bacterial
Discovery Laboratory, Center for Environment, IST, JNT University Hyderabad, Kukatpally, Hyderabad 500 085, India
| | - Ch Venkata Ramana
- Department
of Plant Sciences, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500 046, India
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Simon O, Klaiber I, Huber A, Pfannstiel J. Comprehensive proteome analysis of the response of Pseudomonas putida KT2440 to the flavor compound vanillin. J Proteomics 2014; 109:212-27. [PMID: 25026441 DOI: 10.1016/j.jprot.2014.07.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 06/25/2014] [Accepted: 07/06/2014] [Indexed: 12/15/2022]
Abstract
UNLABELLED Understanding of the molecular response of bacteria to precursors, products and environmental conditions applied in bioconversions is essential for optimizing whole-cell biocatalysis. To investigate the molecular response of the potential biocatalyst Pseudomonas putida KT2440 to the flavor compound vanillin we applied complementary gel- and LC-MS-based quantitative proteomics approaches. Our comprehensive proteomics survey included cytoplasmic and membrane proteins and led to the identification and quantification of 1614 proteins, corresponding to 30% of the total KT2440 proteome. 662 proteins were altered in abundance during growth on vanillin as sole carbon source as compared to growth on glucose. The proteome response entailed an increased abundance of enzymes involved in vanillin degradation, significant changes in central energy metabolism and an activation of solvent tolerance mechanisms. With respect to vanillin metabolism, particularly enzymes belonging to the β-ketoadipate pathway including a transcriptional regulator and porins specific for vanillin uptake increased in abundance. However, catabolism of vanillin was not dependent on vanillin dehydrogenase (Vdh), as shown by quantitative proteome analysis of a Vdh-deficient KT2440 mutant (GN235). Other aldehyde dehydrogenases that were significantly increased in abundance in response to vanillin may replace Vdh and thus may represent interesting targets for improving vanillin production in P. putida KT2440. BIOLOGICAL SIGNIFICANCE The high demand for the flavor compound vanillin by the food and fragrance industry makes natural vanillin from vanilla pods a scarce and expensive resource rendering its biotechnological production economically attractive. Pseudomonas bacteria are metabolically very versatile and accept a broad range of hydrocarbons as carbon source making them suitable candidates for bioconversion processes. This work describes the impact of vanillin on the metabolism of the reference strain P. putida KT2440 on a proteome wide scale. The high proteome coverage of our proteomics survey allowed us to analyze the regulation of whole protein networks instead of single proteins. We were able to reconstruct the complete degradation pathway of vanillin and to monitor the changes in the energy metabolism of KT2440 induced by vanillin as sole carbon source. Vanillin dehydrogenase (Vdh) was not mandatory for vanillin degradation in KT2440 and may be substituted by other aldehyde dehydrogenases that were up-regulated in a wild-type as well as in a Vdh-deficient strain in the presence of vanillin. Aldehyde dehydrogenases, vanillin specific porins and efflux pump systems identified in study will be interesting targets for optimization of vanillin production in Pseudomonas bacteria. Furthermore, several mechanisms of solvent tolerance were induced by vanillin in KT2440. These include increased abundance of several efflux pump systems, chaperones as well as enzymes involved in cyclopropane fatty acid synthesis and trehalose formation. The present work will deepen the understanding of metabolism of aromatic compounds in P. putida and may lead to a more comprehensive understanding of solvent tolerance mechanisms in Gram-negative bacteria in general. Moreover, it will serve as a basis for further strain developments for a biotechnological production of vanillin in P. putida KT2440 or other Pseudomonas strains, highlighting the role of proteomics surveys as a powerful screening technology.
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Affiliation(s)
- Oliver Simon
- Department of Biosensorics, Institute of Physiology, University of Hohenheim, August von Hartmann-Str. 3, 70599 Stuttgart, Germany
| | - Iris Klaiber
- Proteomics Core Facility of the Life Science Center, University of Hohenheim, August von Hartmann-Str. 3, 70599 Stuttgart, Germany
| | - Armin Huber
- Department of Biosensorics, Institute of Physiology, University of Hohenheim, August von Hartmann-Str. 3, 70599 Stuttgart, Germany; Proteomics Core Facility of the Life Science Center, University of Hohenheim, August von Hartmann-Str. 3, 70599 Stuttgart, Germany
| | - Jens Pfannstiel
- Proteomics Core Facility of the Life Science Center, University of Hohenheim, August von Hartmann-Str. 3, 70599 Stuttgart, Germany.
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Murínová S, Dercová K. Response mechanisms of bacterial degraders to environmental contaminants on the level of cell walls and cytoplasmic membrane. Int J Microbiol 2014; 2014:873081. [PMID: 25057269 PMCID: PMC4099092 DOI: 10.1155/2014/873081] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/12/2014] [Accepted: 05/27/2014] [Indexed: 11/18/2022] Open
Abstract
Bacterial strains living in the environment must cope with the toxic compounds originating from humans production. Surface bacterial structures, cell wall and cytoplasmic membrane, surround each bacterial cell and create selective barriers between the cell interior and the outside world. They are a first site of contact between the cell and toxic compounds. Organic pollutants are able to penetrate into cytoplasmic membrane and affect membrane physiological functions. Bacteria had to evolve adaptation mechanisms to counteract the damage originated from toxic contaminants and to prevent their accumulation in cell. This review deals with various adaptation mechanisms of bacterial cell concerning primarily the changes in cytoplasmic membrane and cell wall. Cell adaptation maintains the membrane fluidity status and ratio between bilayer/nonbilayer phospholipids as well as the efflux of toxic compounds, protein repair mechanisms, and degradation of contaminants. Low energy consumption of cell adaptation is required to provide other physiological functions. Bacteria able to survive in toxic environment could help us to clean contaminated areas when they are used in bioremediation technologies.
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Affiliation(s)
- Slavomíra Murínová
- Department of Biochemical Technology, Faculty of Chemical and Food Technology, Institute of Biotechnology and Food Science, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia
- Water Research Institute, Nábrežie arm. gen. L. Svobodu 5, 812 49 Bratislava, Slovakia
| | - Katarína Dercová
- Department of Biochemical Technology, Faculty of Chemical and Food Technology, Institute of Biotechnology and Food Science, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia
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AraC/XylS family stress response regulators Rob, SoxS, PliA, and OpiA in the fire blight pathogen Erwinia amylovora. J Bacteriol 2014; 196:3098-110. [PMID: 24936054 DOI: 10.1128/jb.01838-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcriptional regulators of the AraC/XylS family have been associated with multidrug resistance, organic solvent tolerance, oxidative stress, and virulence in clinically relevant enterobacteria. In the present study, we identified four homologous AraC/XylS regulators, Rob, SoxS, PliA, and OpiA, from the fire blight pathogen Erwinia amylovora Ea1189. Previous studies have shown that the regulators MarA, Rob, and SoxS from Escherichia coli mediate multiple-antibiotic resistance, primarily by upregulating the AcrAB-TolC efflux system. However, none of the four AraC/XylS regulators from E. amylovora was able to induce a multidrug resistance phenotype in the plant pathogen. Overexpression of rob led to a 2-fold increased expression of the acrA gene. However, the rob-overexpressing strain showed increased resistance to only a limited number of antibiotics. Furthermore, Rob was able to induce tolerance to organic solvents in E. amylovora by mechanisms other than efflux. We demonstrated that SoxS from E. amylovora is involved in superoxide resistance. A soxS-deficient mutant of Ea1189 was not able to grow on agar plates supplemented with the superoxide-generating agent paraquat. Furthermore, expression of soxS was induced by redox cycling agents. We identified two novel members of the AraC/XylS family in E. amylovora. PliA was highly upregulated during the early infection phase in apple rootstock and immature pear fruits. Multiple compounds were able to induce the expression of pliA, including apple leaf extracts, phenolic compounds, redox cycling agents, heavy metals, and decanoate. OpiA was shown to play a role in the regulation of osmotic and alkaline pH stress responses.
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40
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Schrewe M, Julsing MK, Bühler B, Schmid A. Whole-cell biocatalysis for selective and productive C-O functional group introduction and modification. Chem Soc Rev 2014; 42:6346-77. [PMID: 23475180 DOI: 10.1039/c3cs60011d] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
During the last decades, biocatalysis became of increasing importance for chemical and pharmaceutical industries. Regarding regio- and stereospecificity, enzymes have shown to be superior compared to traditional chemical synthesis approaches, especially in C-O functional group chemistry. Catalysts established on a process level are diverse and can be classified along a functional continuum starting with single-step biotransformations using isolated enzymes or microbial strains towards fermentative processes with recombinant microorganisms containing artificial synthetic pathways. The complex organization of respective enzymes combined with aspects such as cofactor dependency and low stability in isolated form often favors the use of whole cells over that of isolated enzymes. Based on an inventory of the large spectrum of biocatalytic C-O functional group chemistry, this review focuses on highlighting the potentials, limitations, and solutions offered by the application of self-regenerating microbial cells as biocatalysts. Different cellular functionalities are discussed in the light of their (possible) contribution to catalyst efficiency. The combined achievements in the areas of protein, genetic, metabolic, and reaction engineering enable the development of whole-cell biocatalysts as powerful tools in organic synthesis.
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Affiliation(s)
- Manfred Schrewe
- Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227 Dortmund, Germany
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41
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Mandalakis M, Panikov N, Dai S, Ray S, Karger BL. Comparative proteomic analysis reveals mechanistic insights into Pseudomonas putida F1 growth on benzoate and citrate. AMB Express 2013; 3:64. [PMID: 24156539 PMCID: PMC3827995 DOI: 10.1186/2191-0855-3-64] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 10/21/2013] [Indexed: 11/10/2022] Open
Abstract
Pseudomonas species are capable to proliferate under diverse environmental conditions and thus have a significant bioremediation potential. To enhance our understanding of their metabolic versatility, this study explores the changes in the proteome and physiology of Pseudomonas putida F1 resulting from its growth on benzoate, a moderate toxic compound that can be catabolized, and citrate, a carbon source that is assimilated through central metabolic pathways. A series of repetitive batch cultivations were performed to ensure a complete adaptation of the bacteria to each of these contrasting carbon sources. After several growth cycles, cell growth stabilized at the maximum level and exhibited a reproducible growth profile. The specific growth rates measured for benzoate (1.01 ± 0.11 h-1) and citrate (1.11 ± 0.12 h-1) were similar, while a higher yield was observed for benzoate (0.6 and 0.3 g cell mass per g of benzoate and citrate, respectively), reflecting the different degrees of carbon reduction in the two substrates. Comparative proteomic analysis revealed an enrichment of several oxygenases/dehydrogenases in benzoate-grown cells, indicative of the higher carbon reduction of benzoate. Moreover, the upregulation of all 14 proteins implicated in benzoate degradation via the catechol ortho-cleavage pathway was observed, while several stress-response proteins were increased to aid cells to cope with benzoate toxicity. Unexpectedly, citrate posed more challenges than benzoate in the maintenance of pH homeostasis, as indicated by the enhancement of the Na+/H+ antiporter and carbonic anhydrase. The study provides important mechanistic insights into Pseudomonas adaptation to varying carbon sources that are of great relevance to bioremediation efforts.
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42
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Fu F, Cheng VWT, Wu Y, Tang Y, Weiner JH, Li L. Comparative proteomic and metabolomic analysis of Staphylococcus warneri SG1 cultured in the presence and absence of butanol. J Proteome Res 2013; 12:4478-89. [PMID: 23961999 DOI: 10.1021/pr400533m] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The complete genome of the solvent tolerant Staphylococcus warneri SG1 was recently published. This Gram-positive bacterium is tolerant to a large spectrum of organic solvents including short-chain alcohols, alkanes, esters and cyclic aromatic compounds. In this study, we applied a two-dimensional liquid chromatography (2D-LC) mass spectrometry (MS) shotgun approach, in combination with quantitative 2-MEGA (dimethylation after guanidination) isotopic labeling, to compare the proteomes of SG1 grown under butanol-free and butanol-challenged conditions. In total, 1585 unique proteins (representing 65% of the predicted open reading frames) were identified, covering all major metabolic pathways. Of the 967 quantifiable proteins by 2-MEGA labeling, 260 were differentially expressed by at least 1.5-fold. These proteins are involved in energy metabolism, oxidative stress response, lipid and cell envelope biogenesis, or have chaperone functions. We also applied differential isotope labeling LC-MS to probe metabolite changes in key metabolic pathways upon butanol stress. This is the first comprehensive proteomic and metabolomic study of S. warneri SG1 and presents an important step toward understanding its physiology and mechanism of solvent tolerance.
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Affiliation(s)
- Feifei Fu
- Department of Chemistry and ‡Department of Biochemistry, University of Alberta , Edmonton, Alberta T6G2G2, Canada
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43
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Cray JA, Bell ANW, Bhaganna P, Mswaka AY, Timson DJ, Hallsworth JE. The biology of habitat dominance; can microbes behave as weeds? Microb Biotechnol 2013; 6:453-92. [PMID: 23336673 PMCID: PMC3918151 DOI: 10.1111/1751-7915.12027] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 12/03/2012] [Indexed: 02/06/2023] Open
Abstract
Competition between microbial species is a product of, yet can lead to a reduction in, the microbial diversity of specific habitats. Microbial habitats can resemble ecological battlefields where microbial cells struggle to dominate and/or annihilate each other and we explore the hypothesis that (like plant weeds) some microbes are genetically hard-wired to behave in a vigorous and ecologically aggressive manner. These 'microbial weeds' are able to dominate the communities that develop in fertile but uncolonized--or at least partially vacant--habitats via traits enabling them to out-grow competitors; robust tolerances to habitat-relevant stress parameters and highly efficient energy-generation systems; avoidance of or resistance to viral infection, predation and grazers; potent antimicrobial systems; and exceptional abilities to sequester and store resources. In addition, those associated with nutritionally complex habitats are extraordinarily versatile in their utilization of diverse substrates. Weed species typically deploy multiple types of antimicrobial including toxins; volatile organic compounds that act as either hydrophobic or highly chaotropic stressors; biosurfactants; organic acids; and moderately chaotropic solutes that are produced in bulk quantities (e.g. acetone, ethanol). Whereas ability to dominate communities is habitat-specific we suggest that some microbial species are archetypal weeds including generalists such as: Pichia anomala, Acinetobacter spp. and Pseudomonas putida; specialists such as Dunaliella salina, Saccharomyces cerevisiae, Lactobacillus spp. and other lactic acid bacteria; freshwater autotrophs Gonyostomum semen and Microcystis aeruginosa; obligate anaerobes such as Clostridium acetobutylicum; facultative pathogens such as Rhodotorula mucilaginosa, Pantoea ananatis and Pseudomonas aeruginosa; and other extremotolerant and extremophilic microbes such as Aspergillus spp., Salinibacter ruber and Haloquadratum walsbyi. Some microbes, such as Escherichia coli, Mycobacterium smegmatis and Pseudoxylaria spp., exhibit characteristics of both weed and non-weed species. We propose that the concept of nonweeds represents a 'dustbin' group that includes species such as Synodropsis spp., Polypaecilum pisce, Metschnikowia orientalis, Salmonella spp., and Caulobacter crescentus. We show that microbial weeds are conceptually distinct from plant weeds, microbial copiotrophs, r-strategists, and other ecophysiological groups of microorganism. Microbial weed species are unlikely to emerge from stationary-phase or other types of closed communities; it is open habitats that select for weed phenotypes. Specific characteristics that are common to diverse types of open habitat are identified, and implications of weed biology and open-habitat ecology are discussed in the context of further studies needed in the fields of environmental and applied microbiology.
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Affiliation(s)
- Jonathan A Cray
- School of Biological Sciences, MBC, Queen's University BelfastBelfast, BT9 7BL, Northern Ireland, UK
| | - Andrew N W Bell
- School of Biological Sciences, MBC, Queen's University BelfastBelfast, BT9 7BL, Northern Ireland, UK
| | - Prashanth Bhaganna
- School of Biological Sciences, MBC, Queen's University BelfastBelfast, BT9 7BL, Northern Ireland, UK
| | - Allen Y Mswaka
- School of Biological Sciences, MBC, Queen's University BelfastBelfast, BT9 7BL, Northern Ireland, UK
| | - David J Timson
- School of Biological Sciences, MBC, Queen's University BelfastBelfast, BT9 7BL, Northern Ireland, UK
| | - John E Hallsworth
- School of Biological Sciences, MBC, Queen's University BelfastBelfast, BT9 7BL, Northern Ireland, UK
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Udaondo Z, Molina L, Daniels C, Gómez MJ, Molina-Henares MA, Matilla MA, Roca A, Fernández M, Duque E, Segura A, Ramos JL. Metabolic potential of the organic-solvent tolerant Pseudomonas putida DOT-T1E deduced from its annotated genome. Microb Biotechnol 2013; 6:598-611. [PMID: 23815283 PMCID: PMC3918161 DOI: 10.1111/1751-7915.12061] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 03/27/2013] [Accepted: 03/31/2013] [Indexed: 11/30/2022] Open
Abstract
Pseudomonas putida DOT-T1E is an organic solvent tolerant strain capable of degrading aromatic hydrocarbons. Here we report the DOT-T1E genomic sequence (6 394 153 bp) and its metabolic atlas based on the classification of enzyme activities. The genome encodes for at least 1751 enzymatic reactions that account for the known pattern of C, N, P and S utilization by this strain. Based on the potential of this strain to thrive in the presence of organic solvents and the subclasses of enzymes encoded in the genome, its metabolic map can be drawn and a number of potential biotransformation reactions can be deduced. This information may prove useful for adapting desired reactions to create value-added products. This bioengineering potential may be realized via direct transformation of substrates, or may require genetic engineering to block an existing pathway, or to re-organize operons and genes, as well as possibly requiring the recruitment of enzymes from other sources to achieve the desired transformation. Funding Information Work in our laboratory was supported by Fondo Social Europeo and Fondos FEDER from the European Union, through several projects (BIO2010-17227, Consolider-Ingenio CSD2007-00005, Excelencia 2007 CVI-3010, Excelencia 2011 CVI-7391 and EXPLORA BIO2011-12776-E).
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Affiliation(s)
- Zulema Udaondo
- Estación Experimental del Zadín-CSIC, Profesor Albareda 1, 18008 Granada, Spain
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Moreno R, Rojo F. The contribution of proteomics to the unveiling of the survival strategies used by Pseudomonas putida
in changing and hostile environments. Proteomics 2013; 13:2822-30. [DOI: 10.1002/pmic.201200503] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 02/26/2013] [Accepted: 03/28/2013] [Indexed: 01/14/2023]
Affiliation(s)
- Renata Moreno
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología; CSIC Madrid Spain
| | - Fernando Rojo
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología; CSIC Madrid Spain
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46
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Herbst FA, Taubert M, Jehmlich N, Behr T, Schmidt F, von Bergen M, Seifert J. Sulfur-34S stable isotope labeling of amino acids for quantification (SULAQ34) of proteomic changes in Pseudomonas fluorescens during naphthalene degradation. Mol Cell Proteomics 2013; 12:2060-9. [PMID: 23603340 DOI: 10.1074/mcp.m112.025627] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The relative quantification of proteins is one of the major techniques used to elucidate physiological reactions. Because it allows one to avoid artifacts due to chemical labeling, the metabolic introduction of heavy isotopes into proteins and peptides is the preferred method for relative quantification. For eukaryotic cells, stable isotope labeling by amino acids in cell culture (SILAC) has become the gold standard and can be readily applied in a vast number of scenarios. In the microbial realm, with its highly versatile metabolic capabilities, SILAC is often not feasible, and the use of other (13)C or (15)N labeled substrates might not be practical. Here, the incorporation of heavy sulfur isotopes is shown to be a useful alternative. We introduce (34)S stable isotope labeling of amino acids for quantification and the corresponding tools required for spectra extraction and disintegration of the isotopic overlaps caused by the small mass shift. As proof of principle, we investigated the proteomic changes related to naphthalene degradation in P. fluorescens ATCC 17483 and uncovered a specific oxidative-stress-like response.
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Affiliation(s)
- Florian-Alexander Herbst
- Helmholtz Centre for Environmental Research, Department of Proteomics, Permoserstrasse 15, 04318 Leipzig, Germany
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Ni Y, Song L, Qian X, Sun Z. Proteomic analysis of Pseudomonas putida reveals an organic solvent tolerance-related gene mmsB. PLoS One 2013; 8:e55858. [PMID: 23409067 PMCID: PMC3569466 DOI: 10.1371/journal.pone.0055858] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 01/03/2013] [Indexed: 11/19/2022] Open
Abstract
Organic solvents are toxic to most microorganisms. However, some organic-solvent-tolerant (OST) bacteria tolerate the destructive effects of organic solvent through various accommodative mechanisms. In this work, we developed an OST adapted strain Pseudomonas putida JUCT1 that could grow in the presence of 60% (v/v) cyclohexane. Two-dimensional gel electrophoresis was used to compare and analyze the total cellular protein of P. putida JUCT1 growing with or without 60% (v/v) cyclohexane. Under different solvent conditions, five high-abundance protein spots whose intensity values show over 60% discrepancies were identified by MALDI-TOF/TOF spectra. Specifically, they are arginine deiminase, carbon-nitrogen hydrolase family putative hydrolase, 3-hydroxyisobutyrate dehydrogenase, protein chain elongation factor EF-Ts, and isochorismatase superfamily hydrolase. The corresponding genes of the latter three proteins, mmsB, tsf, and PSEEN0851, were separately expressed in Escherichia coli to evaluate their effect on OST properties of the host strain. In the presence of 4% (v/v) cyclohexane, E. coli harboring mmsB could grow to 1.70 OD(660), whereas cell growth of E. coli JM109 (the control) was completely inhibited by 2% (v/v) cyclohexane. Transformants carrying tsf or PSEEN0851 also showed an increased resistance to cyclohexane and other organic solvents compared with the control. Of these three genes, mmsB exhibited the most prominent effect on increasing OST of E. coli. Less oxidation product of cyclohexane was detected because mmsB transformants might help keep a lower intracellular cyclohexane level. This study demonstrates a feasible approach for elucidating OST mechanisms of microorganisms, and provides molecular basis to construct organic-solvent-tolerant strains for industrial applications.
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Affiliation(s)
- Ye Ni
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, PR China.
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Global stress response in a prokaryotic model of DJ-1-associated Parkinsonism. J Bacteriol 2013; 195:1167-78. [PMID: 23292772 DOI: 10.1128/jb.02202-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
YajL is the most closely related Escherichia coli homolog of Parkinsonism-associated protein DJ-1, a protein with a yet-undefined function in the oxidative-stress response. YajL protects cells against oxidative-stress-induced protein aggregation and functions as a covalent chaperone for the thiol proteome, including FeS proteins. To clarify the cellular responses to YajL deficiency, transcriptional profiling of the yajL mutant was performed. Compared to the parental strain, the yajL mutant overexpressed genes coding for chaperones, proteases, chemical chaperone transporters, superoxide dismutases, catalases, peroxidases, components of thioredoxin and glutaredoxin systems, iron transporters, ferritins and FeS cluster biogenesis enzymes, DNA repair proteins, RNA chaperones, and small regulatory RNAs. It also overexpressed the RNA polymerase stress sigma factors sigma S (multiple stresses) and sigma 32 (protein stress) and activated the OxyR and SoxRS oxidative-stress transcriptional regulators, which together trigger the global stress response. The yajL mutant also overexpressed genes involved in septation and adopted a shorter and rounder shape characteristic of stressed bacteria. Biochemical experiments showed that this upregulation of many stress genes resulted in increased expression of stress proteins and improved biochemical function. Thus, protein defects resulting from the yajL mutation trigger the onset of a robust and global stress response in a prokaryotic model of DJ-1-associated Parkinsonism.
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Coronado E, Roggo C, Johnson DR, van der Meer JR. Genome-Wide Analysis of Salicylate and Dibenzofuran Metabolism in Sphingomonas Wittichii RW1. Front Microbiol 2012; 3:300. [PMID: 22936930 PMCID: PMC3425912 DOI: 10.3389/fmicb.2012.00300] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 07/28/2012] [Indexed: 11/13/2022] Open
Abstract
Sphingomonas wittichii RW1 is a bacterium isolated for its ability to degrade the xenobiotic compounds dibenzodioxin and dibenzofuran (DBF). A number of genes involved in DBF degradation have been previously characterized, such as the dxn cluster, dbfB, and the electron transfer components fdx1, fdx3, and redA2. Here we use a combination of whole genome transcriptome analysis and transposon library screening to characterize RW1 catabolic and other genes implicated in the reaction to or degradation of DBF. To detect differentially expressed genes upon exposure to DBF, we applied three different growth exposure experiments, using either short DBF exposures to actively growing cells or growing them with DBF as sole carbon and energy source. Genome-wide gene expression was examined using a custom-made microarray. In addition, proportional abundance determination of transposon insertions in RW1 libraries grown on salicylate or DBF by ultra-high throughput sequencing was used to infer genes whose interruption caused a fitness loss for growth on DBF. Expression patterns showed that batch and chemostat growth conditions, and short or long exposure of cells to DBF produced very different responses. Numerous other uncharacterized catabolic gene clusters putatively involved in aromatic compound metabolism increased expression in response to DBF. In addition, only very few transposon insertions completely abolished growth on DBF. Some of those (e.g., in dxnA1) were expected, whereas others (in a gene cluster for phenylacetate degradation) were not. Both transcriptomic data and transposon screening suggest operation of multiple redundant and parallel aromatic pathways, depending on DBF exposure. In addition, increased expression of other non-catabolic genes suggests that during initial exposure, S. wittichii RW1 perceives DBF as a stressor, whereas after longer exposure, the compound is recognized as a carbon source and metabolized using several pathways in parallel.
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Affiliation(s)
- Edith Coronado
- Department of Fundamental Microbiology, University of Lausanne Lausanne, Switzerland
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Production host selection for asymmetric styrene epoxidation: Escherichia coli vs. solvent-tolerant Pseudomonas. ACTA ACUST UNITED AC 2012; 39:1125-33. [DOI: 10.1007/s10295-012-1126-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 03/28/2012] [Indexed: 10/28/2022]
Abstract
Abstract
Selection of the ideal microbe is crucial for whole-cell biotransformations, especially if the target reaction intensively interacts with host cell functions. Asymmetric styrene epoxidation is an example of a reaction which is strongly dependent on the host cell owing to its requirement for efficient cofactor regeneration and stable expression of the styrene monooxygenase genes styAB. On the other hand, styrene epoxidation affects the whole-cell biocatalyst, because it involves toxic substrate and products besides the burden of additional (recombinant) enzyme synthesis. With the aim to compare two fundamentally different strain engineering strategies, asymmetric styrene epoxidation by StyAB was investigated using the engineered wild-type strain Pseudomonas sp. strain VLB120ΔC, a styrene oxide isomerase (StyC) knockout strain able to accumulate (S)-styrene oxide, and recombinant E. coli JM101 carrying styAB on the plasmid pSPZ10. Their performance was analyzed during fed-batch cultivation in two-liquid phase biotransformations with respect to specific activity, volumetric productivity, product titer, tolerance of toxic substrate and products, by-product formation, and product yield on glucose. Thereby, Pseudomonas sp. strain VLB120ΔC proved its great potential by tolerating high styrene oxide concentrations and by the absence of by-product formation. The E. coli-based catalyst, however, showed higher specific activities and better yields on glucose. The results not only show the importance but also the complexity of host cell selection and engineering. Finding the optimal strain engineering strategy requires profound understanding of bioprocess and biocatalyst operation. In this respect, a possible negative influence of solvent tolerance on yield and activity is discussed.
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