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Wang Z, Sun J, Yang P, Zhang W, Jiang Y, Liu Q, Yang Y, Hao R, Guo G, Huo W, Zhang Q, Li Q. Molecular Analysis of Indole and Skatole Decomposition Metabolism in Acinetobacter piscicola p38 Utilizing Biochemical and Omics Approaches. Microorganisms 2024; 12:1792. [PMID: 39338467 PMCID: PMC11434297 DOI: 10.3390/microorganisms12091792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Revised: 08/24/2024] [Accepted: 08/26/2024] [Indexed: 09/30/2024] Open
Abstract
Indole and skatole (3-methylindole, C9H9N) are common nitrogen-containing heterocyclic pollutants found in waste, wastewater treatment plants, and public restrooms and are the most notorious compounds in animal feces. Biodegradation was considered a feasible method for the removal of indole and skatole, but a comprehensive understanding of the metabolic pathways under both aerobic and anaerobic conditions was lacking, and the functional genes responsible for skatole biodegradation remained a mystery. Through metagenomic and gene cluster functional analysis, Acinetobacter piscicola p38 (NCBI: CP167896), genes 1650 (styrene monooxygenase: ACDW34_08180), and 1687 (styrene monooxygenase: ACDW34_08350) were identified as having the potential to degrade indole and skatole. The heterologous expression results demonstrate that the genes 1650 and 1651 (flavin reductase: ACDW34_08185), when combined, are capable of degrading indole, while the genes 1687 and 1688 (flavin reductase: ACDW34_08355), in combination, can degrade indole as well as skatole. These reactions necessitate the involvement of flavin reductase and NAD(P)H to catalyze the oxygenation process. This work aimed to provide new experimental evidence for the biodegradation of indole and skatole. This study offered new insights into our understanding of skatole degradation. The Acinetobacter_piscicola p38 strain provided an effective bacterial resource for the bioremediation of fecal indole and skatole.
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Affiliation(s)
- Zhonghao Wang
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Jiajin Sun
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Pu Yang
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Wanjun Zhang
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Yihong Jiang
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Qiang Liu
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Yunqi Yang
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Ruirong Hao
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Gang Guo
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Wenjie Huo
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
| | - Qiang Zhang
- College of Resources and Environment, Shanxi Agricultural University, Taigu 030800, China;
| | - Qinghong Li
- College of Animal Science, Shanxi Agricultural University, Taigu 030800, China; (Z.W.); (J.S.); (P.Y.); (W.Z.); (Y.J.); (Q.L.); (Y.Y.); (R.H.); (G.G.); (W.H.)
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2
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Yin S, Li Y, Hou J. Expression of the two-component regulator StyS/StyR enhanced transcription of the styrene monooxygenase gene styAB and indigo biosynthesis in Escherichia coli. Enzyme Microb Technol 2024; 174:110381. [PMID: 38134734 DOI: 10.1016/j.enzmictec.2023.110381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023]
Abstract
Indigo, an economically important dye, could be biosynthesized from indole by catalysis of the styrene monooxygenase StyAB. To enhance indigo biosynthesis, the styAB gene and its transcription regulator gene styS/styR in styrene catabolism were cloned from Pseudomonas putida and coexpressed in Escherichia coli. The presence of the intact regulator gene styS/styR dramatically increased the transcriptional levels of styA and styB by approximately 120-fold in the recombinant strain SRAB2 with coexpression of styS/styR and styAB compared to the control strain ABST with solo expression of styAB. A yield of 67.6 mg/L indigo was detected in strain SRAB2 after 24 h of fermentation with 120 μg/mL indole, which was approximately 14-fold higher than that in the control strain ABST. The maximum yield of indigo was produced from 160 μg/mL indole in fermentation of strain SRAB2. However, the addition of styrene to the media significantly inhibited the transcription of styA and styB and consequent indigo biosynthesis in recombinant E. coli strains. Furthermore, the substitution of indole with tryptophan as the fermentation substrate remarkably boosted indigo production, and the maximal yield of 565.6 mg/L was detected in strain SRAB2 in fermentation with 1.2 mg/mL tryptophan. The results revealed that the regulation of styAB transcription by the two-component regulator StyS/StyR in styrene catabolism in P. putida was effective in E. coli, which provided a new strategy for the development of engineered E. coli strains with the capacity for highly efficient indigo production.
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Affiliation(s)
- Sheng Yin
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology & Business University, Beijing 100048, China; Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology & Business University, Beijing 100048, China; School of Food & Health, Beijing Technology & Business University, Beijing 100048, China.
| | - Yujie Li
- School of Food & Health, Beijing Technology & Business University, Beijing 100048, China
| | - Jialing Hou
- School of Food & Health, Beijing Technology & Business University, Beijing 100048, China
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Calatrava V, Hom EF, Guan Q, Llamas A, Fernández E, Galván A. Genetic evidence for algal auxin production in Chlamydomonas and its role in algal-bacterial mutualism. iScience 2024; 27:108762. [PMID: 38269098 PMCID: PMC10805672 DOI: 10.1016/j.isci.2023.108762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 10/31/2023] [Accepted: 12/14/2023] [Indexed: 01/26/2024] Open
Abstract
Interactions between algae and bacteria are ubiquitous and play fundamental roles in nutrient cycling and biomass production. Recent studies have shown that the plant auxin indole acetic acid (IAA) can mediate chemical crosstalk between algae and bacteria, resembling its role in plant-bacterial associations. Here, we report a mechanism for algal extracellular IAA production from L-tryptophan mediated by the enzyme L-amino acid oxidase (LAO1) in the model Chlamydomonas reinhardtii. High levels of IAA inhibit algal cell multiplication and chlorophyll degradation, and these inhibitory effects can be relieved by the presence of the plant-growth-promoting bacterium (PGPB) Methylobacterium aquaticum, whose growth is mutualistically enhanced by the presence of the alga. These findings reveal a complex interplay of microbial auxin production and degradation by algal-bacterial consortia and draws attention to potential ecophysiological roles of terrestrial microalgae and PGPB in association with land plants.
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Affiliation(s)
- Victoria Calatrava
- Departamento de Bioquímica y Biología Molecular. Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Erik F.Y. Hom
- Department of Biology and Center for Biodiversity and Conservation Research, University of Mississippi, University, MS 38677-1848, USA
| | - Qijie Guan
- Department of Biology and Center for Biodiversity and Conservation Research, University of Mississippi, University, MS 38677-1848, USA
| | - Angel Llamas
- Departamento de Bioquímica y Biología Molecular. Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Emilio Fernández
- Departamento de Bioquímica y Biología Molecular. Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Aurora Galván
- Departamento de Bioquímica y Biología Molecular. Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain
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4
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Pan Z, Tao D, Ren M, Cheng L. A Combinational Optimization Method for Efficient Production of Indigo by the Recombinant Escherichia coli with Expression of Monooxygenase and Malate Dehydrogenase. Foods 2023; 12:foods12030502. [PMID: 36766031 PMCID: PMC9914922 DOI: 10.3390/foods12030502] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/16/2023] [Accepted: 01/19/2023] [Indexed: 01/24/2023] Open
Abstract
Indigo pigment is a widely used pigment, and the use of biosynthesis to ferment indigo has become a hot research topic. Based on previous research, the indigo could be biosynthesized via the styrene oxygenation pathway, which is regulated by intracellular redox-cofactor rebalancing. In this work, the malate dehydrogenase (mdh) gene was selected as an NADH regeneration element to improve the intracellular cofactor regeneration level, and it was co-expressed with the styrene monooxygenase (styAB) gene by pET-28a(+) vector in E. coli for enhancing indigo production. The PT7 and Pcat promoter was constructed to change the styAB gene and mdh gene from inducible expression to constitutive expression, since the expressing vector pET-28a(+) needs to be induced by IPTG. After different strategies of genetic manipulations, the styAB gene and mdh gene were successfully constitutively co-expressed by different promoters in E. coli, which obviously enhanced the monooxygenase activity and indigo production, as expected. The maximum yield of indigo in recombinant strains was up to 787.25 mg/L after 24 h of fermentation using 2.0 g/L tryptophan as substrate, which was nearly the highest indigo-producing ability using tryptophan as substrate in recent studies. In summary, this work provided a theoretical basis for the subsequent study of indigo biosynthesis and probably revealed a new insight into the construction of indigo biosynthesis cell factory for application.
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Affiliation(s)
| | | | | | - Lei Cheng
- Correspondence: ; Tel.: +86-10-68985252
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5
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Li F, Deng H, Zhong B, Ruan B, Zhao X, Luo X. Identification of an indole biodegradation gene cluster from Providencia rettgeri and its contribution in selectively biosynthesizing Tyrian purple. Front Bioeng Biotechnol 2023; 10:1109929. [PMID: 36704308 PMCID: PMC9871250 DOI: 10.3389/fbioe.2022.1109929] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 12/23/2022] [Indexed: 01/12/2023] Open
Abstract
Tyrian purple, mainly composed of 6, 6'-dibromoindigo, is a precious dye extracted from sea snails. In this study, we found Tyrian purple can be selectively produced by a bacterial strain GS-2 when fed with 6-bromotryptophan in the presence of tryptophan. This GS-2 strain was then identified as Providencia rettgeri based on bacterial genome sequencing analysis. An indole degradation gene cluster for indole metabolism was identified from this GS-2 strain. The heterologous expression of the indole degradation gene cluster in Escherichia coli BL21 (DE3) and in vitro enzymatic reaction demonstrated that the indole biodegradation gene cluster may contribute to selectively biosynthesizing Tyrian purple. To further explore the underlying mechanism of the selectivity, we explored the intermediates in this indole biodegradation pathway using liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS), which indicated that the indole biodegradation pathway in Providencia rettgeri is the catechol pathway. Interestingly, the monooxygenase GS-C co-expressed with its corresponding reductase GS-D in the cluster has better activity for the biosynthesis of Tyrian purple compared with the previously reported monooxygenase from Methylophaga aminisulfidivorans (MaFMO) or Streptomyces cattleya cytochrome P450 enzyme (CYP102G4). This is the first study to show the existence of an indole biodegradation pathway in Providencia rettgeri, and the indole biodegradation gene cluster can contribute to the selective production of Tyrian purple.
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Affiliation(s)
- Feifei Li
- School of Life Sciences, Inner Mongolia University, Hohhot, China,Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicines, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,Center for Synthetic Biochemistry, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Huaxiang Deng
- Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicines, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,Center for Synthetic Biochemistry, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Biming Zhong
- Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicines, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,Center for Synthetic Biochemistry, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Banlai Ruan
- Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicines, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,Center for Synthetic Biochemistry, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Xixi Zhao
- Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicines, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,Center for Synthetic Biochemistry, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,*Correspondence: Xixi Zhao, ; Xiaozhou Luo,
| | - Xiaozhou Luo
- School of Life Sciences, Inner Mongolia University, Hohhot, China,Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicines, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,Center for Synthetic Biochemistry, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China,*Correspondence: Xixi Zhao, ; Xiaozhou Luo,
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6
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Conway JM, Walton WG, Salas-González I, Law TF, Lindberg CA, Crook LE, Kosina SM, Fitzpatrick CR, Lietzan AD, Northen TR, Jones CD, Finkel OM, Redinbo MR, Dangl JL. Diverse MarR bacterial regulators of auxin catabolism in the plant microbiome. Nat Microbiol 2022; 7:1817-1833. [PMID: 36266335 PMCID: PMC9613470 DOI: 10.1038/s41564-022-01244-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 09/02/2022] [Indexed: 11/13/2022]
Abstract
Chemical signalling in the plant microbiome can have drastic effects on microbial community structure, and on host growth and development. Previously, we demonstrated that the auxin metabolic signal interference performed by the bacterial genus Variovorax via an auxin degradation locus was essential for maintaining stereotypic root development in an ecologically relevant bacterial synthetic community. Here, we dissect the Variovorax auxin degradation locus to define the genes iadDE as necessary and sufficient for indole-3-acetic acid (IAA) degradation and signal interference. We determine the crystal structures and binding properties of the operon's MarR-family repressor with IAA and other auxins. Auxin degradation operons were identified across the bacterial tree of life and we define two distinct types on the basis of gene content and metabolic products: iac-like and iad-like. The structures of MarRs from representatives of each auxin degradation operon type establish that each has distinct IAA-binding pockets. Comparison of representative IAA-degrading strains from diverse bacterial genera colonizing Arabidopsis plants show that while all degrade IAA, only strains containing iad-like auxin-degrading operons interfere with auxin signalling in a complex synthetic community context. This suggests that iad-like operon-containing bacterial strains, including Variovorax species, play a key ecological role in modulating auxins in the plant microbiome.
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Affiliation(s)
- Jonathan M Conway
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - William G Walton
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Isai Salas-González
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Theresa F Law
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Chloe A Lindberg
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Laura E Crook
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Suzanne M Kosina
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Connor R Fitzpatrick
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Adam D Lietzan
- Division of Oral and Craniofacial Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Trent R Northen
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Corbin D Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Omri M Finkel
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Plant and Environmental Sciences, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Matthew R Redinbo
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Biochemistry and Biophysics, and the Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Jeffery L Dangl
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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7
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Production of Indigo by Recombinant Escherichia coli with Expression of Monooxygenase, Tryptophanase, and Molecular Chaperone. Foods 2022; 11:foods11142117. [PMID: 35885360 PMCID: PMC9320885 DOI: 10.3390/foods11142117] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/04/2022] [Accepted: 07/14/2022] [Indexed: 12/04/2022] Open
Abstract
Indigo is an important pigment widely used in industries of food, cosmetics, and textile. In this work, the styrene monooxygenase StyAB from Pseudomonas putida was co-expressed with the tryptophanase TnaA and the chaperone groES-groEL in Escherichia coli for indigo production. Over-expression of the gene styAB endowed the recombinant E. coli AB with the capacity of indigo biosynthesis from indole and tryptophan. Tryptophan fermentation in E. coli AB generated about five times more indigo than that from indole, and the maximum 530 mg/L of indigo was obtained from 1.2 mg/mL of tryptophan. The gene TnaA was then co-expressed with styAB, and the tryptophanase activity significantly increased in the recombinant E. coli ABT. However, TnaA expression led to a decrease in the activity of StyAB and indigo yield in E. coli ABT. Furthermore, the plasmid pGro7 harboring groES-groEL was introduced into E. coli AB, which obviously promoted the activity of StyAB and accelerated indigo biosynthesis in the recombinant E. coli ABP. In addition, the maximum yield of indigo was further increased to 550 mg/L from 1.2 mg/mL of tryptophan in E. coli ABP. The genetic manipulation strategy proposed in this work could provide new insights into construction of indigo biosynthesis cell factory for industrial production.
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8
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Zhao S, Chen X, Sun Q, Wang F, Hu C, Guo L, Bai J, Yu H. Label-Free Quantitative Proteomic Analysis of the Global Response to Indole-3-Acetic Acid in Newly Isolated Pseudomonas sp. Strain LY1. Front Microbiol 2021; 12:694874. [PMID: 34447357 PMCID: PMC8383072 DOI: 10.3389/fmicb.2021.694874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/25/2021] [Indexed: 11/13/2022] Open
Abstract
Indole-3-acetic acid (IAA), known as a common plant hormone, is one of the most distributed indole derivatives in the environment, but the degradation mechanism and cellular response network to IAA degradation are still not very clear. The objective of this study was to elucidate the molecular mechanisms of IAA degradation at the protein level by a newly isolated strain Pseudomonas sp. LY1. Label-free quantitative proteomic analysis of strain LY1 cultivated with IAA or citrate/NH4Cl was applied. A total of 2,604 proteins were identified, and 227 proteins have differential abundances in the presence of IAA, including 97 highly abundant proteins and 130 less abundant proteins. Based on the proteomic analysis an IAA degrading (iad) gene cluster in strain LY1 containing IAA transformation genes (organized as iadHABICDEFG), genes of the β-ketoadipate pathway for catechol and protocatechuate degradation (catBCA and pcaABCDEF) were identified. The iadA, iadB, and iadE-disrupted mutants lost the ability to grow on IAA, which confirmed the role of the iad cluster in IAA degradation. Degradation intermediates were analyzed by HPLC, LC-MS, and GC-MS analysis. Proteomic analysis and identified products suggested that multiple degradation pathways existed in strain LY1. IAA was initially transformed to dioxindole-3-acetic acid, which was further transformed to isatin. Isatin was then transformed to isatinic acid or catechol. An in-depth data analysis suggested oxidative stress in strain LY1 during IAA degradation, and the abundance of a series of proteins was upregulated to respond to the stress, including reaction oxygen species (ROS) scavenging, protein repair, fatty acid synthesis, RNA protection, signal transduction, chemotaxis, and several membrane transporters. The findings firstly explained the adaptation mechanism of bacteria to IAA degradation.
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Affiliation(s)
- Shuxue Zhao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China.,Shandong Province Key Laboratory of Applied Mycology, School of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Xi Chen
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China
| | - Qianshu Sun
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China.,Shandong Province Key Laboratory of Applied Mycology, School of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Fei Wang
- Shandong Province Key Laboratory of Applied Mycology, School of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Chunhui Hu
- Shandong Province Key Laboratory of Applied Mycology, School of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Lizhong Guo
- Shandong Province Key Laboratory of Applied Mycology, School of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Jie Bai
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China
| | - Hao Yu
- Shandong Province Key Laboratory of Applied Mycology, School of Life Sciences, Qingdao Agricultural University, Qingdao, China
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9
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Laird TS, Flores N, Leveau JHJ. Bacterial catabolism of indole-3-acetic acid. Appl Microbiol Biotechnol 2020; 104:9535-9550. [PMID: 33037916 DOI: 10.1007/s00253-020-10938-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/21/2020] [Accepted: 09/27/2020] [Indexed: 12/18/2022]
Abstract
Indole-3-acetic acid (IAA) is a molecule with the chemical formula C10H9NO2, with a demonstrated presence in various environments and organisms, and with a biological function in several of these organisms, most notably in plants where it acts as a growth hormone. The existence of microorganisms with the ability to catabolize or assimilate IAA has long been recognized. To date, two sets of gene clusters underlying this property in bacteria have been identified and characterized: one (iac) is responsible for the aerobic degradation of IAA into catechol, and another (iaa) for the anaerobic conversion of IAA to 2-aminobenzoyl-CoA. Here, we summarize the literature on the products, reactions, and pathways that these gene clusters encode. We explore two hypotheses about the benefit that iac/iaa gene clusters confer upon their bacterial hosts: (1) exploitation of IAA as a source of carbon, nitrogen, and energy; and (2) interference with IAA-dependent processes and functions in other organisms, including plants. The evidence for both hypotheses will be reviewed for iac/iaa-carrying model strains of Pseudomonas putida, Enterobacter soli, Acinetobacter baumannii, Paraburkholderia phytofirmans, Caballeronia glathei, Aromatoleum evansii, and Aromatoleum aromaticum, more specifically in the context of access to IAA in the environments from which these bacteria were originally isolated, which include not only plants, but also soils and sediment, as well as patients in hospital environments. We end the mini-review with an outlook for iac/iaa-inspired research that addresses current gaps in knowledge, biotechnological applications of iac/iaa-encoded enzymology, and the use of IAA-destroying bacteria to treat pathologies related to IAA excess in plants and humans. KEY POINTS: • The iac/iaa gene clusters encode bacterial catabolism of the plant growth hormone IAA. • Plants are not the only environment where IAA or IAA-degrading bacteria can be found. • The iac/iaa genes allow growth at the expense of IAA; other benefits remain unknown.
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Affiliation(s)
- Tyler S Laird
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616, USA
| | - Neptali Flores
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616, USA
| | - Johan H J Leveau
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616, USA.
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10
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Duca DR, Glick BR. Indole-3-acetic acid biosynthesis and its regulation in plant-associated bacteria. Appl Microbiol Biotechnol 2020; 104:8607-8619. [PMID: 32875364 DOI: 10.1007/s00253-020-10869-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 08/19/2020] [Accepted: 08/26/2020] [Indexed: 11/28/2022]
Abstract
Numerous studies have reported the stimulation of plant growth following inoculation with an IAA-producing PGPB. However, the specific mode of IAA production by the PGPB is rarely elucidated. In part, this is due to the overwhelming complexity of IAA biosynthesis and regulation. The promiscuity of the enzymes implicated in IAA biosynthesis adds another element of complexity when attempting to decipher their role in IAA biosynthesis. To date, the majority of research on IAA biosynthesis describes three separate pathways classified in terms of their intermediates-indole acetonitrile (IAN), indole acetamide (IAM), and indole pyruvic acid (IPA). Each of these pathways is mediated by a set of enzymes, many of which are traditionally assumed to exist for that specific catalytic role. This lends the possibility of missing other, novel, enzymes that may also incidentally serve that function. Some of these pathways are constitutively expressed, while others are inducible. Some enzymes involved in IAA biosynthesis are known to be regulated by IAA or by IAA precursors, as well as by a multitude of environmental cues. This review aims to provide an update to our current understanding of the biosynthesis and regulation of IAA in bacteria. KEY POINTS: • IAA produced by PGPB improves bacterial stress tolerance and promotes plant growth. • Bacterial IAA biosynthesis is convoluted; multiple interdependent pathways. • Biosynthesis of IAA is regulated by IAA, IAA-precursors, and environmental factors.
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Affiliation(s)
- Daiana R Duca
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
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11
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Djami-Tchatchou AT, Harrison GA, Harper CP, Wang R, Prigge MJ, Estelle M, Kunkel BN. Dual Role of Auxin in Regulating Plant Defense and Bacterial Virulence Gene Expression During Pseudomonas syringae PtoDC3000 Pathogenesis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:1059-1071. [PMID: 32407150 PMCID: PMC7810136 DOI: 10.1094/mpmi-02-20-0047-r] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Modification of host hormone biology is a common strategy used by plant pathogens to promote disease. For example, the bacterial pathogen strain Pseudomonas syringae DC3000 (PtoDC3000) produces the plant hormone auxin (indole-3-acetic acid [IAA]) to promote PtoDC3000 growth in plant tissue. Previous studies suggest that auxin may promote PtoDC3000 pathogenesis through multiple mechanisms, including both suppression of salicylic acid (SA)-mediated host defenses and via an unknown mechanism that appears to be independent of SA. To test if host auxin signaling is important during pathogenesis, we took advantage of Arabidopsis thaliana lines impaired in either auxin signaling or perception. We found that disruption of auxin signaling in plants expressing an inducible dominant axr2-1 mutation resulted in decreased bacterial growth and that this phenotype was suppressed by introducing the sid2-2 mutation, which impairs SA synthesis. Thus, host auxin signaling is required for normal susceptibility to PtoDC3000 and is involved in suppressing SA-mediated defenses. Unexpectedly, tir1 afb1 afb4 afb5 quadruple-mutant plants lacking four of the six known auxin coreceptors that exhibit decreased auxin perception, supported increased levels of bacterial growth. This mutant exhibited elevated IAA levels and reduced SA-mediated defenses, providing additional evidence that auxin promotes disease by suppressing host defense. We also investigated the hypothesis that IAA promotes PtoDC3000 virulence through a direct effect on the pathogen and found that IAA modulates expression of virulence genes, both in culture and in planta. Thus, in addition to suppressing host defenses, IAA acts as a microbial signaling molecule that regulates bacterial virulence gene expression.
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Affiliation(s)
| | | | - Chris P. Harper
- Department of Biology, Washington University, St. Louis, MO, U.S.A
| | - Renhou Wang
- Division of Biological Sciences, Section of Cell & Developmental Biology, University California San Diego, San Diego, CA, U.S.A
| | - Michael J. Prigge
- Division of Biological Sciences, Section of Cell & Developmental Biology, University California San Diego, San Diego, CA, U.S.A
| | - Mark Estelle
- Division of Biological Sciences, Section of Cell & Developmental Biology, University California San Diego, San Diego, CA, U.S.A
| | - Barbara N. Kunkel
- Department of Biology, Washington University, St. Louis, MO, U.S.A
- Corresponding author: B. N. Kunkel;
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12
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Legein M, Smets W, Vandenheuvel D, Eilers T, Muyshondt B, Prinsen E, Samson R, Lebeer S. Modes of Action of Microbial Biocontrol in the Phyllosphere. Front Microbiol 2020; 11:1619. [PMID: 32760378 PMCID: PMC7372246 DOI: 10.3389/fmicb.2020.01619] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/22/2020] [Indexed: 12/12/2022] Open
Abstract
A fast-growing field of research focuses on microbial biocontrol in the phyllosphere. Phyllosphere microorganisms possess a wide range of adaptation and biocontrol factors, which allow them to adapt to the phyllosphere environment and inhibit the growth of microbial pathogens, thus sustaining plant health. These biocontrol factors can be categorized in direct, microbe-microbe, and indirect, host-microbe, interactions. This review gives an overview of the modes of action of microbial adaptation and biocontrol in the phyllosphere, the genetic basis of the mechanisms, and examples of experiments that can detect these mechanisms in laboratory and field experiments. Detailed insights in such mechanisms are key for the rational design of novel microbial biocontrol strategies and increase crop protection and production. Such novel biocontrol strategies are much needed, as ensuring sufficient and consistent food production for a growing world population, while protecting our environment, is one of the biggest challenges of our time.
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Affiliation(s)
- Marie Legein
- Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Wenke Smets
- Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Dieter Vandenheuvel
- Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Tom Eilers
- Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Babette Muyshondt
- Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Els Prinsen
- Laboratory for Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Roeland Samson
- Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Sarah Lebeer
- Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
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13
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Bioconversion of Biologically Active Indole Derivatives with Indole-3-Acetic Acid-Degrading Enzymes from Caballeronia glathei DSM50014. Biomolecules 2020; 10:biom10040663. [PMID: 32344740 PMCID: PMC7225977 DOI: 10.3390/biom10040663] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/18/2020] [Accepted: 04/21/2020] [Indexed: 02/08/2023] Open
Abstract
A plant auxin hormone indole-3-acetic acid (IAA) can be assimilated by bacteria as an energy and carbon source, although no degradation has been reported for indole-3-propionic acid and indole-3-butyric acid. While significant efforts have been made to decipher the Iac (indole-3-acetic acid catabolism)-mediated IAA degradation pathway, a lot of questions remain regarding the mechanisms of individual reactions, involvement of specific Iac proteins, and the overall reaction scheme. This work was aimed at providing new experimental evidence regarding the biodegradation of IAA and its derivatives. Here, it was shown that Caballeronia glathei strain DSM50014 possesses a full iac gene cluster and is able to use IAA as a sole source of carbon and energy. Next, IacE was shown to be responsible for the conversion of 2-oxoindole-3-acetic acid (Ox-IAA) intermediate into the central intermediate 3-hydroxy-2-oxindole-3-acetic acid (DOAA) without the requirement for IacB. During this reaction, the oxygen atom incorporated into Ox-IAA was derived from water. Finally, IacA and IacE were shown to convert a wide range of indole derivatives, including indole-3-propionic acid and indole-3-butyric acid, into corresponding DOAA homologs. This work provides novel insights into Iac-mediated IAA degradation and demonstrates the versatility and substrate scope of IacA and IacE enzymes.
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14
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Heine T, Großmann C, Hofmann S, Tischler D. Indigoid dyes by group E monooxygenases: mechanism and biocatalysis. Biol Chem 2020; 400:939-950. [PMID: 30844759 DOI: 10.1515/hsz-2019-0109] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 02/19/2019] [Indexed: 11/15/2022]
Abstract
Since ancient times, people have been attracted by dyes and they were a symbol of power. Some of the oldest dyes are indigo and its derivative Tyrian purple, which were extracted from plants and snails, respectively. These 'indigoid dyes' were and still are used for coloration of textiles and as a food additive. Traditional Chinese medicine also knows indigoid dyes as pharmacologically active compounds and several studies support their effects. Further, they are interesting for future technologies like organic electronics. In these cases, especially the indigo derivatives are of interest but unfortunately hardly accessible by chemical synthesis. In recent decades, more and more enzymes have been discovered that are able to produce these indigoid dyes and therefore have gained attention from the scientific community. In this study, group E monooxygenases (styrene monooxygenase and indole monooxygenase) were used for the selective oxygenation of indole (derivatives). It was possible for the first time to show that the product of the enzymatic reaction is an epoxide. Further, we synthesized and extracted indigoid dyes and could show that there is only minor by-product formation (e.g. indirubin or isoindigo). Thus, group E monooxygenase can be an alternative biocatalyst for the biosynthesis of indigoid dyes.
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Affiliation(s)
- Thomas Heine
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, D-09599 Freiberg, Germany
| | - Carolin Großmann
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, D-09599 Freiberg, Germany
| | - Sarah Hofmann
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, D-09599 Freiberg, Germany
| | - Dirk Tischler
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, D-09599 Freiberg, Germany.,Microbial Biotechnology, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
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15
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Fabara AN, Fraaije MW. An overview of microbial indigo-forming enzymes. Appl Microbiol Biotechnol 2019; 104:925-933. [PMID: 31834440 PMCID: PMC6962290 DOI: 10.1007/s00253-019-10292-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/23/2019] [Accepted: 11/28/2019] [Indexed: 11/03/2022]
Abstract
Indigo is one of the oldest textile dyes and was originally prepared from plant material. Nowadays, indigo is chemically synthesized at a large scale to satisfy the demand for dyeing jeans. The current indigo production processes are based on fossil feedstocks; therefore, it is highly attractive to develop a more sustainable and environmentally friendly biotechnological process for the production of this popular dye. In the past decades, a number of natural and engineered enzymes have been identified that can be used for the synthesis of indigo. This mini-review provides an overview of the various microbial enzymes which are able to produce indigo and discusses the advantages and disadvantages of each biocatalytic system.
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Affiliation(s)
- Andrea N Fabara
- Molecular Enzymology group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Marco W Fraaije
- Molecular Enzymology group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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16
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Mexia N, Koutrakis S, He G, Skaltsounis AL, Denison MS, Magiatis P. A Biomimetic, One-Step Transformation of Simple Indolic Compounds to Malassezia-Related Alkaloids with High AhR Potency and Efficacy. Chem Res Toxicol 2019; 32:2238-2249. [PMID: 31647221 DOI: 10.1021/acs.chemrestox.9b00270] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Malassezia furfur isolates from diseased skin preferentially biosynthesize compounds which are among the most active known aryl-hydrocarbon receptor (AhR) inducers, such as indirubin, tryptanthrin, indolo[3,2-b]carbazole, and 6-formylindolo[3,2-b]carbazole. In our effort to study their production from Malassezia spp., we investigated the role of indole-3-carbaldehyde (I3A), the most abundant metabolite of Malassezia when grown on tryptophan agar, as a possible starting material for the biosynthesis of the alkaloids. Treatment of I3A with H2O2 and use of catalysts like diphenyldiselenide resulted in the simultaneous one-step transformation of I3A to indirubin and tryptanthrin in good yields. The same reaction was first applied on simple indole and then on substituted indoles and indole-3-carbaldehydes, leading to a series of mono- and bisubstituted indirubins and tryptanthrins bearing halogens, alkyl, or carbomethoxy groups. Afterward, they were evaluated for their AhR agonist activity in recombinant human and mouse hepatoma cell lines containing a stably transfected AhR-response luciferase reporter gene. Among them, 3,9-dibromotryptanthrin was found to be equipotent to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as an AhR agonist, and 3-bromotryptanthrin was 10-times more potent than TCDD in the human HG2L7.5c1 cell line. In contrast, 3,9-dibromotryptanthrin and 3-bromotryptanthrin were ∼4000 and >10,000 times less potent than TCDD in the mouse H1L7.5c3 cell line, respectively, demonstrating that they are species-specific AhR agonists. Involvement of the AhR in the action of 3-bromotryptanthrin was confirmed by the ability of the AhR antagonists CH223191 and SR1 to inhibit 3-bromotryptanthrin-dependent reporter gene induction in human HG2L7.5c1 cells. In conclusion, I3A can be the starting material used by Malassezia for the production of both indirubin and tryptanthrin through an oxidation mechanism, and modification of these compounds can produce some highly potent, efficacious and species-selective AhR agonists.
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Affiliation(s)
- Nikitia Mexia
- Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy , National and Kapodistrian University of Athens , Athens 15771 , Greece
| | - Stamatis Koutrakis
- Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy , National and Kapodistrian University of Athens , Athens 15771 , Greece
| | - Guochun He
- Department of Environmental Toxicology , University of California, Davis , Davis , California 95616 , United States
| | - Alexios-Leandros Skaltsounis
- Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy , National and Kapodistrian University of Athens , Athens 15771 , Greece
| | - Michael S Denison
- Department of Environmental Toxicology , University of California, Davis , Davis , California 95616 , United States
| | - Prokopios Magiatis
- Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy , National and Kapodistrian University of Athens , Athens 15771 , Greece.,Department of Environmental Toxicology , University of California, Davis , Davis , California 95616 , United States
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17
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Crocker L, Fruk L. Flavin Conjugated Polydopamine Nanoparticles Displaying Light-Driven Monooxygenase Activity. Front Chem 2019; 7:278. [PMID: 31080793 PMCID: PMC6497766 DOI: 10.3389/fchem.2019.00278] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/04/2019] [Indexed: 11/13/2022] Open
Abstract
A hybrid of flavin and polydopamine (PDA) has been explored as a photocatalyst, drawing inspiration from natural flavoenzymes. Light-driven monoxygenase activity has been demonstrated through the oxidation of indole under blue light irradiation in ambient conditions, to afford indigo and indirubin dyes. Compared to riboflavin, a flavin-polydopamine hybrid is shown to be more resistant to photobleaching and more selective toward dye production. In addition, it has been demonstrated that it can be recycled from the solution and used for up to four cycles without a marked loss of activity, which is a significant improvement compared to other heterogenous flavin catalysts. The mechanism of action has been explored, indicating that the PDA shell plays an important role in the stabilization of the intermediate flavin-peroxy species, an active component of the catalytic system rather than acting only as a passive nanocarrier of active centers.
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Affiliation(s)
- Leander Crocker
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Ljiljana Fruk
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
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18
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Visca P, Pisa F, Imperi F. The antimetabolite 3-bromopyruvate selectively inhibits Staphylococcus aureus. Int J Antimicrob Agents 2018; 53:449-455. [PMID: 30472291 DOI: 10.1016/j.ijantimicag.2018.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/15/2018] [Accepted: 11/17/2018] [Indexed: 12/12/2022]
Abstract
Increased antibacterial resistance jeopardizes current therapeutic strategies to control infections, soliciting the development of novel antibacterial drugs with new mechanisms of action. This study reports the discovery of potent and selective antistaphylococcal activity of 3-bromopyruvate (3BP), an antimetabolite in preclinical development as an anticancer drug. 3BP showed bactericidal activity against Staphylococcus aureus, with active concentrations comparable with those reported to be effective against cancer cells. In contrast, no relevant activity was observed against other ESKAPE bacteria (Enterococcus faecium, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.). The antistaphylococcal activity of 3BP was confirmed using a panel of human and veterinary strains, including multi-drug-resistant isolates. 3BP showed highest antibacterial activity under conditions that increase its stability (acidic pH) or promote S. aureus fermentative metabolism (anaerobiosis), although 3BP was also able to kill metabolically inactive cells. 3BP showed synergism with gentamicin, and also disrupted preformed S. aureus biofilms at concentrations only slightly higher than those inhibiting planktonic cells. This study unravels novel antibacterial and antibiofilm activities for the anticancer drug 3BP, paving the way for further preclinical studies.
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Affiliation(s)
- Paolo Visca
- Department of Sciences, University 'Roma Tre', Rome, Italy
| | - Federica Pisa
- Department of Sciences, University 'Roma Tre', Rome, Italy; Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Francesco Imperi
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy.
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19
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Traglia G, Chiem K, Quinn B, Fernandez JS, Montaña S, Almuzara M, Mussi MA, Tolmasky ME, Iriarte A, Centrón D, Ramírez MS. Genome sequence analysis of an extensively drug-resistant Acinetobacter baumannii indigo-pigmented strain depicts evidence of increase genome plasticity. Sci Rep 2018; 8:16961. [PMID: 30446709 PMCID: PMC6240043 DOI: 10.1038/s41598-018-35377-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 10/29/2018] [Indexed: 01/02/2023] Open
Abstract
Acinetobacter baumannii is a multidrug resistant nosocomial pathogen that shows an outstanding ability to undergo genetic exchange, thereby acquiring different traits that contribute to its success. In this work, we identified genetic features of an indigo-pigmented A. baumannii strain (Ab33405) that belongs to the clonal complex CC113B/CC79P. Ab33405 possesses a high number of genes coding for antibiotic resistance and virulence factors that may contribute to its survival, not only in the human host, but also in the hospital environment. Thirteen genes conferring resistance to different antibiotic families (trimethoprim, florfenicol, β-lactams, aminoglycosides and sulfonamide) as well as the adeIJK genes and the capsule locus (KL) and outer core locus (OCL) were identified. Ab33405 includes 250 unique genes and a significant number of elements associated with Horizontal Gene Transfer, such as insertion sequences and transposons, genomic islands and prophage sequences. Also, the indigo-pigmented uncommon phenotype that could be associated with the monooxygenase or dioxygenase enzyme coded for by the iacA gene within the iac cluster was probably conferred by insertion of a 18-kb DNA fragment into the iacG gene belonging to this cluster. The Ab33405 genome includes all type VI secretion system genes and killing assays showed the ability of Ab33045 to kill Escherichia coli. In addition, Ab33405 can modulate susceptibility antibiotics when exposed to blue light.
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Affiliation(s)
- German Traglia
- Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Kevin Chiem
- Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Brettni Quinn
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Jennifer S Fernandez
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Sabrina Montaña
- Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Marisa Almuzara
- Laboratorio de Bacteriología, Hospital Interzonal de Agudos Eva Perón, San Martín Buenos Aires, Argentina
| | - María Alejandra Mussi
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI- CONICET), Rosario, Argentina
| | - Marcelo E Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA
| | - Andres Iriarte
- Laboratorio de Biología Computacional, Dpto. de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Daniela Centrón
- Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Soledad Ramírez
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA.
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20
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Ma Q, Zhang X, Qu Y. Biodegradation and Biotransformation of Indole: Advances and Perspectives. Front Microbiol 2018; 9:2625. [PMID: 30443243 PMCID: PMC6221969 DOI: 10.3389/fmicb.2018.02625] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 10/15/2018] [Indexed: 11/17/2022] Open
Abstract
Indole is long regarded as a typical N-heterocyclic aromatic pollutant in industrial and agricultural wastewater, and recently it has been identified as a versatile signaling molecule with wide environmental distributions. An exponentially growing number of researches have been reported on indole due to its significant roles in bacterial physiology, pathogenesis, animal behavior and human diseases. From the viewpoint of both environmental bioremediation and biological studies, the researches on metabolism and fates of indole are important to realize environmental treatment and illuminate its biological function. Indole can be produced from tryptophan by tryptophanase in many bacterial species. Meanwhile, various bacterial strains have obtained the ability to transform and degrade indole. The characteristics and pathways for indole degradation have been investigated for a century, and the functional genes for indole aerobic degradation have also been uncovered recently. Interestingly, many oxygenases have proven to be able to oxidize indole to indigo, and this historic and motivating case for biological applications has attracted intensive attention for decades. Herein, the bacteria, enzymes and pathways for indole production, biodegradation and biotransformation are systematically summarized, and the future researches on indole-microbe interactions are also prospected.
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Affiliation(s)
- Qiao Ma
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian, China
| | - Xuwang Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Food and Environment, Dalian University of Technology, Panjin, China
| | - Yuanyuan Qu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
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Biological roles of indole-3-acetic acid in Acinetobacter baumannii. Microbiol Res 2018; 216:30-39. [DOI: 10.1016/j.micres.2018.08.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/28/2018] [Accepted: 08/02/2018] [Indexed: 11/18/2022]
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22
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iac Gene Expression in the Indole-3-Acetic Acid-Degrading Soil Bacterium Enterobacter soli LF7. Appl Environ Microbiol 2018; 84:AEM.01057-18. [PMID: 30054366 DOI: 10.1128/aem.01057-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/21/2018] [Indexed: 12/14/2022] Open
Abstract
We show for soil bacterium Enterobacter soli LF7 that the possession of an indole-3-acetic acid catabolic (iac) gene cluster is causatively linked to the ability to utilize the plant hormone indole-3-acetic acid (IAA) as a carbon and energy source. Genome-wide transcriptional profiling by mRNA sequencing revealed that these iac genes, chromosomally arranged as iacHABICDEFG and coding for the transformation of IAA to catechol, were the most highly induced (>29-fold) among the relatively few (<1%) differentially expressed genes in response to IAA. Also highly induced and immediately downstream of the iac cluster were genes for a major facilitator superfamily protein (mfs) and enzymes of the β-ketoadipate pathway (pcaIJD-catBCA), which channels catechol into central metabolism. This entire iacHABICDEFG-mfs-pcaIJD-catBCA gene set was constitutively expressed in an iacR deletion mutant, confirming the role of iacR, annotated as coding for a MarR-type regulator and located upstream of iacH, as a repressor of iac gene expression. In E. soli LF7 carrying the DNA region upstream of iacH fused to a promoterless gfp gene, green fluorescence accumulated in response to IAA at concentrations as low as 1.6 μM. The iacH promoter region also responded to chlorinated IAA, but not other aromatics tested, indicating a narrow substrate specificity. In an iacR deletion mutant, gfp expression from the iacH promoter region was constitutive, consistent with the predicted role of iacR as a repressor. A deletion analysis revealed putative -35/-10 promoter sequences upstream of iacH, as well as a possible binding site for the IacR repressor.IMPORTANCE Bacterial iac genes code for the enzymatic conversion of the plant hormone indole-3-acetic acid (IAA) to catechol. Here, we demonstrate that the iac genes of soil bacterium Enterobacter soli LF7 enable growth on IAA by coarrangement and coexpression with a set of pca and cat genes that code for complete conversion of catechol to central metabolites. This work contributes in a number of novel and significant ways to our understanding of iac gene biology in bacteria from (non-)plant environments. More specifically, we show that LF7's response to IAA involves derepression of the MarR-type transcriptional regulator IacR, which is quite fast (less than 25 min upon IAA exposure), highly specific (only in response to IAA and chlorinated IAA, and with few genes other than iac, cat, and pca induced), relatively sensitive (low micromolar range), and seemingly tailored to exploit IAA as a source of carbon and energy.
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Heine T, van Berkel WJH, Gassner G, van Pée KH, Tischler D. Two-Component FAD-Dependent Monooxygenases: Current Knowledge and Biotechnological Opportunities. BIOLOGY 2018; 7:biology7030042. [PMID: 30072664 PMCID: PMC6165268 DOI: 10.3390/biology7030042] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 12/11/2022]
Abstract
Flavoprotein monooxygenases create valuable compounds that are of high interest for the chemical, pharmaceutical, and agrochemical industries, among others. Monooxygenases that use flavin as cofactor are either single- or two-component systems. Here we summarize the current knowledge about two-component flavin adenine dinucleotide (FAD)-dependent monooxygenases and describe their biotechnological relevance. Two-component FAD-dependent monooxygenases catalyze hydroxylation, epoxidation, and halogenation reactions and are physiologically involved in amino acid metabolism, mineralization of aromatic compounds, and biosynthesis of secondary metabolites. The monooxygenase component of these enzymes is strictly dependent on reduced FAD, which is supplied by the reductase component. More and more representatives of two-component FAD-dependent monooxygenases have been discovered and characterized in recent years, which has resulted in the identification of novel physiological roles, functional properties, and a variety of biocatalytic opportunities.
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Affiliation(s)
- Thomas Heine
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - George Gassner
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA.
| | - Karl-Heinz van Pée
- Allgemeine Biochemie, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Dirk Tischler
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
- Microbial Biotechnology, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
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Qu Y, Ma Q, Liu Z, Wang W, Tang H, Zhou J, Xu P. Unveiling the biotransformation mechanism of indole in a Cupriavidus sp. strain. Mol Microbiol 2017; 106:905-918. [PMID: 28963777 DOI: 10.1111/mmi.13852] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 01/13/2023]
Abstract
Indole, an important signaling molecule as well as a typical N-heterocyclic aromatic pollutant, is widespread in nature. However, the biotransformation mechanisms of indole are still poorly studied. Here, we sought to unlock the genetic determinants of indole biotransformation in strain Cupriavidus sp. SHE based on genomics, proteomics and functional studies. A total of 177 proteins were notably altered (118 up- and 59 downregulated) in cells grown in indole mineral salt medium when compared with that in sodium citrate medium. RT-qPCR and gene knockout assays demonstrated that an indole oxygenase gene cluster was responsible for the indole upstream metabolism. A functional indole oxygenase, termed IndA, was identified in the cluster, and its catalytic efficiency was higher than those of previously reported indole oxidation enzymes. Furthermore, the indole downstream metabolism was found to proceed via the atypical CoA-thioester pathway rather than conventional gentisate and salicylate pathways. This unusual pathway was catalyzed by a conserved 2-aminobenzoyl-CoA gene cluster, among which the 2-aminobenzoyl-CoA ligase initiated anthranilate transformation. This study unveils the genetic determinants of indole biotransformation and will provide new insights into our understanding of indole biodegradation in natural environments and its functional studies.
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Affiliation(s)
- Yuanyuan Qu
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Qiao Ma
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Ziyan Liu
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Weiwei Wang
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Hongzhi Tang
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Jiti Zhou
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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25
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Kugel S, Baunach M, Baer P, Ishida-Ito M, Sundaram S, Xu Z, Groll M, Hertweck C. Cryptic indole hydroxylation by a non-canonical terpenoid cyclase parallels bacterial xenobiotic detoxification. Nat Commun 2017. [PMID: 28643772 PMCID: PMC5481743 DOI: 10.1038/ncomms15804] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Terpenoid natural products comprise a wide range of molecular architectures that typically result from C–C bond formations catalysed by classical type I/II terpene cyclases. However, the molecular diversity of biologically active terpenoids is substantially increased by fully unrelated, non-canonical terpenoid cyclases. Their evolutionary origin has remained enigmatic. Here we report the in vitro reconstitution of an unusual flavin-dependent bacterial indoloterpenoid cyclase, XiaF, together with a designated flavoenzyme-reductase (XiaP) that mediates a key step in xiamycin biosynthesis. The crystal structure of XiaF with bound FADH2 (at 2.4 Å resolution) and phylogenetic analyses reveal that XiaF is, surprisingly, most closely related to xenobiotic-degrading enzymes. Biotransformation assays show that XiaF is a designated indole hydroxylase that can be used for the production of indigo and indirubin. We unveil a cryptic hydroxylation step that sets the basis for terpenoid cyclization and suggest that the cyclase has evolved from xenobiotics detoxification enzymes. The biosynthesis of xiamycin, an antimicrobial bacterial indolosesquiterpenoid, involves an unusual cyclization cascade. Here, the authors characterise the XiaF enzyme, which resembles xenobiont-degrading enzymes and is responsible for a hidden indole hydroxylation step that triggers the cyclization reaction.
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Affiliation(s)
- Susann Kugel
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Martin Baunach
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Philipp Baer
- Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Mie Ishida-Ito
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Srividhya Sundaram
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Zhongli Xu
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Michael Groll
- Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany.,Natural Product Chemistry, Friedrich Schiller University, 07743 Jena, Germany
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26
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Biochemical and Genetic Bases of Indole-3-Acetic Acid (Auxin Phytohormone) Degradation by the Plant-Growth-Promoting Rhizobacterium Paraburkholderia phytofirmans PsJN. Appl Environ Microbiol 2016; 83:AEM.01991-16. [PMID: 27795307 DOI: 10.1128/aem.01991-16] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 10/14/2016] [Indexed: 12/16/2022] Open
Abstract
Several bacteria use the plant hormone indole-3-acetic acid (IAA) as a sole carbon and energy source. A cluster of genes (named iac) encoding IAA degradation has been reported in Pseudomonas putida 1290, but the functions of these genes are not completely understood. The plant-growth-promoting rhizobacterium Paraburkholderia phytofirmans PsJN harbors iac gene homologues in its genome, but with a different gene organization and context than those of P. putida 1290. The iac gene functions enable P. phytofirmans to use IAA as a sole carbon and energy source. Employing a heterologous expression system approach, P. phytofirmans iac genes with previously undescribed functions were associated with specific biochemical steps. In addition, two uncharacterized genes, previously unreported in P. putida and found to be related to major facilitator and tautomerase superfamilies, are involved in removal of an IAA metabolite called dioxindole-3-acetate. Similar to the case in strain 1290, IAA degradation proceeds through catechol as intermediate, which is subsequently degraded by ortho-ring cleavage. A putative two-component regulatory system and a LysR-type regulator, which apparently respond to IAA and dioxindole-3-acetate, respectively, are involved in iac gene regulation in P. phytofirmans These results provide new insights about unknown gene functions and complex regulatory mechanisms in IAA bacterial catabolism. IMPORTANCE This study describes indole-3-acetic acid (auxin phytohormone) degradation in the well-known betaproteobacterium P. phytofirmans PsJN and comprises a complete description of genes, some of them with previously unreported functions, and the general basis of their gene regulation. This work contributes to the understanding of how beneficial bacteria interact with plants, helping them to grow and/or to resist environmental stresses, through a complex set of molecular signals, in this case through degradation of a highly relevant plant hormone.
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Lin GH, Chen HP, Shu HY. Detoxification of Indole by an Indole-Induced Flavoprotein Oxygenase from Acinetobacter baumannii. PLoS One 2015; 10:e0138798. [PMID: 26390211 PMCID: PMC4577076 DOI: 10.1371/journal.pone.0138798] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 09/03/2015] [Indexed: 11/17/2022] Open
Abstract
Indole, a derivative of the amino acid tryptophan, is a toxic signaling molecule, which can inhibit bacterial growth. To overcome indole-induced toxicity, many bacteria have developed enzymatic defense systems to convert indole to non-toxic, water-insoluble indigo. We previously demonstrated that, like other aromatic compound-degrading bacteria, Acinetobacter baumannii can also convert indole to indigo. However, no work has been published investigating this mechanism. Here, we have shown that the growth of wild-type A. baumannii is severely inhibited in the presence of 3.5 mM indole. However, at lower concentrations, growth is stable, implying that the bacteria may be utilizing a survival mechanism to oxidize indole. To this end, we have identified a flavoprotein oxygenase encoded by the iifC gene of A. baumannii. Further, our results suggest that expressing this recombinant oxygenase protein in Escherichia coli can drive indole oxidation to indigo in vitro. Genome analysis shows that the iif operon is exclusively present in the genomes of A. baumannii and Pseudomonas syringae pv. actinidiae. Quantitative PCR and Western blot analysis also indicate that the iif operon is activated by indole through the AraC-like transcriptional regulator IifR. Taken together, these data suggest that this species of bacteria utilizes a novel indole-detoxification mechanism that is modulated by IifC, a protein that appears to be, at least to some extent, regulated by IifR.
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Affiliation(s)
- Guang-Huey Lin
- Microbial Genetics Laboratory, Department of Microbiology, Tzu-Chi University, Hualien, Taiwan
| | - Hao-Ping Chen
- Department of Biochemistry, School of Medicine, Tzu-Chi University, Hualien, Taiwan
| | - Hung-Yu Shu
- Department of Bioscience Technology, Chang Jung Christian University, Tainan, Taiwan
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28
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Efficient production of indigoidine in Escherichia coli. J Ind Microbiol Biotechnol 2015; 42:1149-55. [PMID: 26109508 DOI: 10.1007/s10295-015-1642-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 06/10/2015] [Indexed: 10/23/2022]
Abstract
Indigoidine is a bacterial natural product with antioxidant and antimicrobial activities. Its bright blue color resembles the industrial dye indigo, thus representing a new natural blue dye that may find uses in industry. In our previous study, an indigoidine synthetase Sc-IndC and an associated helper protein Sc-IndB were identified from Streptomyces chromofuscus ATCC 49982 and successfully expressed in Escherichia coli BAP1 to produce the blue pigment at 3.93 g/l. To further improve the production of indigoidine, in this work, the direct biosynthetic precursor L-glutamine was fed into the fermentation broth of the engineered E. coli strain harboring Sc-IndC and Sc-IndB. The highest titer of indigoidine reached 8.81 ± 0.21 g/l at 1.46 g/l L-glutamine. Given the relatively high price of L-glutamine, a metabolic engineering technique was used to directly enhance the in situ supply of this precursor. A glutamine synthetase gene (glnA) was amplified from E. coli and co-expressed with Sc-indC and Sc-indB in E. coli BAP1, leading to the production of indigoidine at 5.75 ± 0.09 g/l. Because a nitrogen source is required for amino acid biosynthesis, we then tested the effect of different nitrogen-containing salts on the supply of L-glutamine and subsequent indigoidine production. Among the four tested salts including (NH4)2SO4, NH4Cl, (NH4)2HPO4 and KNO3, (NH4)2HPO4 showed the best effect on improving the titer of indigoidine. Different concentrations of (NH4)2HPO4 were added to the fermentation broths of E. coli BAP1/Sc-IndC+Sc-IndB+GlnA, and the titer reached the highest (7.08 ± 0.11 g/l) at 2.5 mM (NH4)2HPO4. This work provides two efficient methods for the production of this promising blue pigment in E. coli.
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29
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Shu HY, Lin LC, Lin TK, Chen HP, Yang HH, Peng KC, Lin GH. Transcriptional regulation of the iac locus from Acinetobacter baumannii by the phytohormone indole-3-acetic acid. Antonie van Leeuwenhoek 2015; 107:1237-47. [PMID: 25726082 DOI: 10.1007/s10482-015-0417-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/24/2015] [Indexed: 11/25/2022]
Abstract
The iac locus is involved in indole-3-acetic acid (IAA) catabolism in Acinetobacter baumannii. Nine structural genes of iac are transcribed in the same direction, whereas iacR, which encodes a MarR-type transcriptional regulator, is transcribed in the opposite direction. The IacA protein, which is encoded by the second structural gene of the iac locus, is expressed in an IAA-dependent manner. Here, we characterized gene expression from this locus in wild type A. baumannii and in an iacR mutant; this revealed that the iacH promoter is negatively regulated by IacR. The transcriptional site of iacH was determined by using 5' rapid amplification of cDNA ends; one IacR-binding site was identified between positions -35 and +28 of the iacH promoter. Sequence analysis and an electrophoretic mobility shift assay indicated that recombinant IacR binds specifically to a sequence with dyad symmetry in the iacR-iacH overlapping promoters in the absence of IAA. In addition, a two-plasmid expression system in Escherichia coli showed that IAA probably serves as a ligand that binds to IacR and releases it from the iacH promoter, thereby allowing RNA polymerase to transcribe iac. Thus, iac is expressed in order to promote IAA degradation, whereas free IacR is required for iac repression. We conclude that IacR serves as a key regulator of IAA degradation in A. baumannii in the rhizosphere. These results provide new insights into the possible role of A. baumannii in the environment.
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Affiliation(s)
- Hung-Yu Shu
- Department of Bioscience Technology, Chang Jung Christian University, Tainan, 711, Taiwan
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30
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Abstract
Indole and its derivatives, including 3-methylindole and 4-chloroindole, are environmental pollutants that are present worldwide. Microbial degradation of indole and its derivatives can occur in several aerobic and anaerobic pathways; these pathways involve different known and characterized genes. In this minireview, we summarize and explain the microbial degradation of indole, indole-3-acetic acid, 4-chloroindole, and methylindole.
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31
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Duca D, Lorv J, Patten CL, Rose D, Glick BR. Indole-3-acetic acid in plant-microbe interactions. Antonie van Leeuwenhoek 2014; 106:85-125. [PMID: 24445491 DOI: 10.1007/s10482-013-0095-y] [Citation(s) in RCA: 325] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 12/07/2013] [Indexed: 01/04/2023]
Abstract
Indole-3-acetic acid (IAA) is an important phytohormone with the capacity to control plant development in both beneficial and deleterious ways. The ability to synthesize IAA is an attribute that many bacteria including both plant growth-promoters and phytopathogens possess. There are three main pathways through which IAA is synthesized; the indole-3-pyruvic acid, indole-3-acetamide and indole-3-acetonitrile pathways. This chapter reviews the factors that effect the production of this phytohormone, the role of IAA in bacterial physiology and in plant-microbe interactions including phytostimulation and phytopathogenesis.
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Affiliation(s)
- Daiana Duca
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada,
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32
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Outbreak of extensively drug-resistant Acinetobacter baumannii indigo-pigmented strains. J Clin Microbiol 2013; 51:3726-30. [PMID: 23985923 DOI: 10.1128/jcm.01388-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii pigmented strains are not common in clinical settings. Here, we report an outbreak caused by indigo-pigmented A. baumannii strains isolated in an acute care hospital in Argentina from March to September 2012. Pan-PCR assays exposed a unique pattern belonging to the recently described regional CC113(B)/CC79(P) clonal complex that confirms the relevant relationships among the indigo-pigmented A. baumannii strains. All of them were extensively drug resistant and harbored different genetic elements associated with horizontal genetic transfer, such as the transposon Tn2006, class 2 integrons, AbaR-type islands, IS125, IS26, strA, strB, florR, and the small recombinase ISCR2 associated with the sul2 gene preceded by ISAba1.
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Fiester SE, Actis LA. Stress responses in the opportunistic pathogen Acinetobacter baumannii. Future Microbiol 2013; 8:353-65. [PMID: 23464372 DOI: 10.2217/fmb.12.150] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Acinetobacter baumannii causes a wide range of severe infections among compromised and injured patients worldwide. The relevance of these infections are, in part, due to the ability of this pathogen to sense and react to environmental and host stress signals, allowing it to persist and disseminate in medical settings and the human host. This review summarizes current knowledge on the roles that environmental and cellular stressors play in the ability of A. baumannii to resist nutrient deprivation, oxidative and nitrosative injury, and even the presence of the commonly used antiseptic ethanol, which could serve as a nutrient- and virulence-enhancing signal rather than just being a convenient disinfectant. Emerging experimental evidence supports the role of some of these responses in the pathogenesis of the infections A. baumannii causes in humans and its capacity to resist antibiotics and host response effectors.
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Affiliation(s)
- Steven E Fiester
- Department of Microbiology, Miami University, Oxford, OH 45056, USA
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Functional characterization of the bacterial iac genes for degradation of the plant hormone indole-3-acetic acid. J Chem Ecol 2013; 39:942-51. [PMID: 23881445 DOI: 10.1007/s10886-013-0324-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 06/29/2013] [Accepted: 07/04/2013] [Indexed: 10/26/2022]
Abstract
Pseudomonas putida 1290 is a model organism for the study of bacterial degradation of the plant hormone indole-3-acetic acid (IAA). This property is encoded by the iac gene cluster. Insertional inactivation and/or deletion of individual iac genes and heterologous expression of the gene cluster in Escherichia coli were combined with mass spectrometry to demonstrate that iac-based degradation of IAA is likely to involve 2-hydroxy-IAA, 3-hydroxy-2-oxo-IAA, and catechol as intermediates. The first gene of the cluster, iacA encodes for the first step in the pathway, and also can convert indole to indoxyl to produce the blue pigment indigo. Transcriptional profiling of iac genes in P. putida 1290 revealed that they were induced in the presence of IAA. Based on results with an iacR knockout, we propose that this gene codes for a repressor of iacA expression and that exposure to IAA relieves this repression. Transformation of P. putida KT2440 (which cannot degrade IAA) with the iac gene cluster conferred the ability to grow on IAA as a sole source of carbon and energy, but not the ability to chemotaxi towards IAA. We could show such tactic response for P. putida 1290, thus representing the first demonstration of bacterial chemotaxis towards IAA. We discuss the ecological significance of our findings, and specifically the following question: under what circumstances do bacteria with the ability to degrade, recognize, and move towards IAA have a selective advantage?
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35
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Nwugo CC, Arivett BA, Zimbler DL, Gaddy JA, Richards AM, Actis LA. Effect of ethanol on differential protein production and expression of potential virulence functions in the opportunistic pathogen Acinetobacter baumannii. PLoS One 2012; 7:e51936. [PMID: 23284824 PMCID: PMC3527336 DOI: 10.1371/journal.pone.0051936] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 11/09/2012] [Indexed: 12/25/2022] Open
Abstract
Acinetobacter baumannii persists in the medical environment and causes severe human nosocomial infections. Previous studies showed that low-level ethanol exposure increases the virulence of A. baumannii ATCC 17978. To better understand the mechanisms involved in this response, 2-D gel electrophoresis combined with mass spectrometry was used to investigate differential protein production in bacteria cultured in the presence or absence of ethanol. This approach showed that the presence of ethanol significantly induces and represses the production of 22 and 12 proteins, respectively. Although over 25% of the ethanol-induced proteins were stress-response related, the overall bacterial viability was uncompromised when cultured under these conditions. Production of proteins involved in lipid and carbohydrate anabolism was increased in the presence of ethanol, a response that correlates with increased carbohydrate biofilm content, enhanced biofilm formation on abiotic surfaces and decrease bacterial motility on semi-solid surfaces. The presence of ethanol also induced the acidification of bacterial cultures and the production of indole-3-acetic acid (IAA), a ubiquitous plant hormone that signals bacterial stress-tolerance and promotes plant-bacteria interactions. These responses could be responsible for the significantly enhanced virulence of A. baumannii ATCC 17978 cells cultured in the presence of ethanol when tested with the Galleria mellonella experimental infection model. Taken together, these observations provide new insights into the effect of ethanol in bacterial virulence. This alcohol predisposes the human host to infections by A. baumannii and could favor the survival and adaptation of this pathogen to medical settings and adverse host environments.
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Affiliation(s)
- Chika C. Nwugo
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Brock A. Arivett
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Daniel L. Zimbler
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Jennifer A. Gaddy
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Ashley M. Richards
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Luis A. Actis
- Department of Microbiology, Miami University, Oxford, Ohio, United States of America
- * E-mail:
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