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Lin T, Feng Y, Miao W, Wang S, Bao Z, Shao Z, Zhang D, Wang X, Jiang H, Zhang H. Elevated temperature alters bacterial community from mutualism to antagonism with Skeletonema costatum: insights into the role of a novel species, Tamlana sp. MS1. mSphere 2024; 9:e0019824. [PMID: 38940599 PMCID: PMC11288006 DOI: 10.1128/msphere.00198-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 05/15/2024] [Indexed: 06/29/2024] Open
Abstract
Skeletonema costatum, a cosmopolitan diatom primarily inhabiting coastal ecosystems, exhibits a typically close yet variable relationship with heterotrophic bacteria. The increasing temperature of surface seawater is expected to substantially affect the viability and ecological dynamics of S. costatum, potentially altering its relationship with bacteria. However, it remains unclear to what extent the elevated temperature could change these relationships. Here, the relationship between axenic S. costatum and natural seawater bacteria underwent a dramatic shift from mutualism to antagonism as the co-culture temperature increased from 20°C to 25°C. The co-occurrence network indicated significantly increased complexity of interaction between S. costatum and bacteria community after temperature elevation, especially with Flavobacteriaceae, implying their potential role in eliminating S. costatum under higher temperatures. Additionally, a Flavobacteriaceae isolate, namely MS1 identified as Tamlana genus, was isolated from the co-culture system at 25°C. MS1 had a remarkable ability to eliminate S. costatum, with the mortality rate at 25°C steadily rising from 30.2% at 48 h to 92.4% at 120 h. However, it promoted algal growth to some extent at 20°C. These results demonstrated that increased temperature promotes MS1 shifts from mutualism to antagonism with S. costatum. According to the comparative genomics analysis, changes in the lifestyle of MS1 were attributed to the increased gliding motility and attachment of MS1 under elevated temperature, enabling it to exert an algicidal effect through direct contact with alga. This investigation provided an advanced understanding of interactions between phytoplankton and bacteria in future warming oceanic ecosystems. IMPORTANCE Ocean warming profoundly influences the growth and metabolism of phytoplankton and bacteria, thereby significantly reshaping their interactions. Previous studies have shown that warming can change bacterial lifestyle from mutualism to antagonism with phytoplankton, but the underlying mechanism remains unclear. In this study, we found that high temperature promotes Tamlana sp. MS1 adhesion to Skeletonema costatum, leading to algal lysis through direct contact, demonstrating a transition in lifestyle from mutualism to antagonism with increasing temperature. Furthermore, the gliding motility of MS1 appears to be pivotal in mediating the transition of its lifestyle. These findings not only advance our understanding of the phytoplankton-bacteria relationship under ocean warming but also offer valuable insights for predicting the impact of warming on phytoplankton carbon sequestration.
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Affiliation(s)
- Tenghui Lin
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, China
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Yumeng Feng
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Wenfei Miao
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Shuqi Wang
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Zhen Bao
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Zeyuan Shao
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Demin Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, China
- School of Marine Sciences, Ningbo University, Ningbo, China
- Key Laboratory of Applied Marine Biotechnology of Department of Education, Ningbo University, Ningbo, China
| | - Xinwei Wang
- School of Marine Sciences, Ningbo University, Ningbo, China
- Key Laboratory of Applied Marine Biotechnology of Department of Education, Ningbo University, Ningbo, China
| | - Haibo Jiang
- School of Marine Sciences, Ningbo University, Ningbo, China
- Key Laboratory of Applied Marine Biotechnology of Department of Education, Ningbo University, Ningbo, China
| | - Huajun Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, China
- School of Marine Sciences, Ningbo University, Ningbo, China
- Key Laboratory of Applied Marine Biotechnology of Department of Education, Ningbo University, Ningbo, China
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2
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Roager L, Athena-Vasileiadi D, Gram L, Sonnenschein EC. Antagonistic activity of Phaeobacter piscinae against the emerging fish pathogen Vibrio crassostreae in aquaculture feed algae. Appl Environ Microbiol 2024; 90:e0143923. [PMID: 38349149 PMCID: PMC10952492 DOI: 10.1128/aem.01439-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 12/21/2023] [Indexed: 03/21/2024] Open
Abstract
Aquaculture provides a rich resource of high-quality protein; however, the production is challenged by emerging pathogens such as Vibrio crassostreae. While probiotic bacteria have been proposed as a sustainable solution to reduce pathogen load in aquaculture, their application requires a comprehensive assessment across the aquaculture food chain. The purpose of this study was to determine the antagonistic effect of the potential probiotic bacterium Phaeobacter piscinae against the emerging fish pathogen V. crassostreae in aquaculture feed algae that can be an entry point for pathogens in fish and shellfish aquaculture. P. piscinae strain S26 produces the antibacterial compound tropodithietic acid (TDA). In a plate-based assay, P. piscinae S26 was equally to more effective than the well-studied Phaeobacter inhibens DSM17395 in its inhibition of the fish pathogens Vibrio anguillarum 90-11-286 and V. crassostreae DMC-1. When co-cultured with the microalgae Tetraselmis suecica and Isochrysis galbana, P. piscinae S26 reduced the maximum cell density of V. crassostreae DMC-1 by 2 log and 3-4 log fold, respectively. A TDA-deficient mutant of P. piscinae S26 inhibited V. crassostreae DMC-1 to a lesser extent than the wild type, suggesting that the antagonistic effect involves TDA and other factors. TDA is the prime antagonistic agent of the inhibition of V. anguillarum 90-11-286. Comparative genomics of V. anguillarum 90-11-286 and V. crassostreae DMC-1 revealed that V. crassostreae DMC-1 carries a greater arsenal of antibiotic resistance genes potentially contributing to the reduced effect of TDA. In conclusion, P. piscinae S26 is a promising new candidate for inhibition of emerging pathogens such as V. crassostreae DMC-1 in algal feed systems and could contribute to a more sustainable aquaculture industry.IMPORTANCEThe globally important production of fish and shellfish in aquaculture is challenged by disease outbreaks caused by pathogens such as Vibrio crassostreae. These outbreaks not only lead to substantial economic loss and environmental damage, but treatment with antibiotics can also lead to antibiotic resistance affecting human health. Here, we evaluated the potential of probiotic bacteria, specifically the newly identified strain Phaeobacter piscinae S26, to counteract these threats in a sustainable manner. Through a systematic assessment of the antagonistic effect of P. piscinae S26 against V. crassostreae DMC-1, particularly within the context of algal feed systems, the study demonstrates the effectiveness of P. piscinae S26 as probiotic and thereby provides a strategic pathway for addressing disease outbreaks in aquaculture. This finding has the potential of significantly contributing to the long-term stability of the industry, highlighting the potential of probiotics as an efficient and environmentally conscious approach to safeguarding aquaculture productivity against the adverse impact of pathogens.
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Affiliation(s)
- Line Roager
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | | | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Eva C. Sonnenschein
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
- Swansea University, College of Science and Engineering, Swansea, Wales, United Kingdom
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3
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Burgunter-Delamare B, Shetty P, Vuong T, Mittag M. Exchange or Eliminate: The Secrets of Algal-Bacterial Relationships. PLANTS (BASEL, SWITZERLAND) 2024; 13:829. [PMID: 38592793 PMCID: PMC10974524 DOI: 10.3390/plants13060829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/09/2024] [Accepted: 03/11/2024] [Indexed: 04/11/2024]
Abstract
Algae and bacteria have co-occurred and coevolved in common habitats for hundreds of millions of years, fostering specific associations and interactions such as mutualism or antagonism. These interactions are shaped through exchanges of primary and secondary metabolites provided by one of the partners. Metabolites, such as N-sources or vitamins, can be beneficial to the partner and they may be assimilated through chemotaxis towards the partner producing these metabolites. Other metabolites, especially many natural products synthesized by bacteria, can act as toxins and damage or kill the partner. For instance, the green microalga Chlamydomonas reinhardtii establishes a mutualistic partnership with a Methylobacterium, in stark contrast to its antagonistic relationship with the toxin producing Pseudomonas protegens. In other cases, as with a coccolithophore haptophyte alga and a Phaeobacter bacterium, the same alga and bacterium can even be subject to both processes, depending on the secreted bacterial and algal metabolites. Some bacteria also influence algal morphology by producing specific metabolites and micronutrients, as is observed in some macroalgae. This review focuses on algal-bacterial interactions with micro- and macroalgal models from marine, freshwater, and terrestrial environments and summarizes the advances in the field. It also highlights the effects of temperature on these interactions as it is presently known.
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Affiliation(s)
- Bertille Burgunter-Delamare
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany; (P.S.); (T.V.)
| | - Prateek Shetty
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany; (P.S.); (T.V.)
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Trang Vuong
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany; (P.S.); (T.V.)
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany; (P.S.); (T.V.)
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, 07743 Jena, Germany
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4
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Wang P, Xiao Y, Gao D, Long Y, Xie Z. The Gene paaZ of the Phenylacetic Acid (PAA) Catabolic Pathway Branching Point and ech outside the PAA Catabolon Gene Cluster Are Synergistically Involved in the Biosynthesis of the Iron Scavenger 7-Hydroxytropolone in Pseudomonas donghuensis HYS. Int J Mol Sci 2023; 24:12632. [PMID: 37628812 PMCID: PMC10454607 DOI: 10.3390/ijms241612632] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
The newly discovered iron scavenger 7-hydroxytropolone (7-HT) is secreted by Pseudomonas donghuensis HYS. In addition to possessing an iron-chelating ability, 7-HT has various other biological activities. However, 7-HT's biosynthetic pathway remains unclear. This study was the first to report that the phenylacetic acid (PAA) catabolon genes in cluster 2 are involved in the biosynthesis of 7-HT and that two genes, paaZ (orf13) and ech, are synergistically involved in the biosynthesis of 7-HT in P. donghuensis HYS. Firstly, gene knockout and a sole carbon experiment indicated that the genes orf17-21 (paaEDCBA) and orf26 (paaG) were involved in the biosynthesis of 7-HT and participated in the PAA catabolon pathway in P. donghuensis HYS; these genes were arranged in gene cluster 2 in P. donghuensis HYS. Interestingly, ORF13 was a homologous protein of PaaZ, but orf13 (paaZ) was not essential for the biosynthesis of 7-HT in P. donghuensis HYS. A genome-wide BLASTP search, including gene knockout, complemented assays, and site mutation, showed that the gene ech homologous to the ECH domain of orf13 (paaZ) is essential for the biosynthesis of 7-HT. Three key conserved residues of ech (Asp39, His44, and Gly62) were identified in P. donghuensis HYS. Furthermore, orf13 (paaZ) could not complement the role of ech in the production of 7-HT, and the single carbon experiment indicated that paaZ mainly participates in PAA catabolism. Overall, this study reveals a natural association between PAA catabolon and the biosynthesis of 7-HT in P. donghuensis HYS. These two genes have a synergistic effect and different functions: paaZ is mainly involved in the degradation of PAA, while ech is mainly related to the biosynthesis of 7-HT in P. donghuensis HYS. These findings complement our understanding of the mechanism of the biosynthesis of 7-HT in the genus Pseudomonas.
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Affiliation(s)
| | | | | | - Yan Long
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China; (P.W.); (Y.X.); (D.G.)
| | - Zhixiong Xie
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China; (P.W.); (Y.X.); (D.G.)
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5
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Abada A, Beiralas R, Narvaez D, Sperfeld M, Duchin-Rapp Y, Lipsman V, Yuda L, Cohen B, Carmieli R, Ben-Dor S, Rocha J, Huang Zhang I, Babbin AR, Segev E. Aerobic bacteria produce nitric oxide via denitrification and promote algal population collapse. THE ISME JOURNAL 2023:10.1038/s41396-023-01427-8. [PMID: 37173383 DOI: 10.1038/s41396-023-01427-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/23/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023]
Abstract
Microbial interactions govern marine biogeochemistry. These interactions are generally considered to rely on exchange of organic molecules. Here we report on a novel inorganic route of microbial communication, showing that algal-bacterial interactions between Phaeobacter inhibens bacteria and Gephyrocapsa huxleyi algae are mediated through inorganic nitrogen exchange. Under oxygen-rich conditions, aerobic bacteria reduce algal-secreted nitrite to nitric oxide (NO) through denitrification, a well-studied anaerobic respiratory mechanism. The bacterial NO is involved in triggering a cascade in algae akin to programmed cell death. During death, algae further generate NO, thereby propagating the signal in the algal population. Eventually, the algal population collapses, similar to the sudden demise of oceanic algal blooms. Our study suggests that the exchange of inorganic nitrogen species in oxygenated environments is a potentially significant route of microbial communication within and across kingdoms.
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Affiliation(s)
- Adi Abada
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Roni Beiralas
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Delia Narvaez
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Martin Sperfeld
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Yemima Duchin-Rapp
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Valeria Lipsman
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Lilach Yuda
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Bar Cohen
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Raanan Carmieli
- Depertment of Chemical Research Support, The Weizmann Institute of Science, Rehovot, Israel
| | - Shifra Ben-Dor
- Department of Life Science Core Facilities, The Weizmann Institute of Science, Rehovot, Israel
| | - Jorge Rocha
- CIDEA Consortium Conacyt-Centro de Investigación en Alimentación y Desarrollo, Hermosillo, Mexico
| | - Irene Huang Zhang
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Andrew R Babbin
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Einat Segev
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel.
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6
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Bech PK, Zhang SD, Henriksen NNSE, Bentzon-Tilia M, Strube ML, Gram L. The potential to produce tropodithietic acid by Phaeobacter inhibens affects the assembly of microbial biofilm communities in natural seawater. NPJ Biofilms Microbiomes 2023; 9:12. [PMID: 36959215 PMCID: PMC10036634 DOI: 10.1038/s41522-023-00379-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 03/10/2023] [Indexed: 03/25/2023] Open
Abstract
Microbial secondary metabolites play important roles in biotic interactions in microbial communities and yet, we do not understand how these compounds impact the assembly and development of microbial communities. To address the implications of microbial secondary metabolite production on biotic interactions in the assembly of natural seawater microbiomes, we constructed a model system where the assembly of a natural seawater biofilm community was influenced by the addition of the marine biofilm forming Phaeobacter inhibens that can produce the antibiotic secondary metabolite tropodithietic acid (TDA), or a mutant incapable of TDA production. Because of the broad antibiotic activity of TDA, we hypothesized that the potential of P. inhibens to produce TDA would strongly affect both biofilm and planktonic community assembly patterns. We show that 1.9 % of the microbial composition variance across both environments could be attributed to the presence of WT P. inhibens, and especially genera of the Bacteriodetes were increased by the presence of the TDA producer. Moreover, network analysis with inferred putative microbial interactions revealed that P. inhibens mainly displayed strong positive associations with genera of the Flavobacteriaceae and Alteromonadaceae, and that P. inhibens acts as a keystone OTU in the biofilm exclusively due to its potential to produce TDA. Our results demonstrate the potential impact of microbial secondary metabolites on microbial interactions and assembly dynamics of complex microbial communities.
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Affiliation(s)
| | - Sheng-Da Zhang
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | | | - Mikkel Bentzon-Tilia
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Mikael Lenz Strube
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark.
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7
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Tanabe Y, Yamaguchi H, Yoshida M, Kai A, Okazaki Y. Characterization of a bloom-associated alphaproteobacterial lineage, 'Candidatus Phycosocius': insights into freshwater algal-bacterial interactions. ISME COMMUNICATIONS 2023; 3:20. [PMID: 36906708 PMCID: PMC10008586 DOI: 10.1038/s43705-023-00228-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/23/2023] [Accepted: 03/01/2023] [Indexed: 03/13/2023]
Abstract
Marine bacterial lineages associated with algal blooms, such as the Roseobacter clade, have been well characterized in ecological and genomic contexts, yet such lineages have rarely been explored in freshwater blooms. This study performed phenotypic and genomic analyses of an alphaproteobacterial lineage 'Candidatus Phycosocius' (denoted the CaP clade), one of the few lineages ubiquitously associated with freshwater algal blooms, and described a novel species: 'Ca. Phycosocius spiralis.' Phylogenomic analyses indicated that the CaP clade is a deeply branching lineage in the Caulobacterales. Pangenome analyses revealed characteristic features of the CaP clade: aerobic anoxygenic photosynthesis and essential vitamin B auxotrophy. Genome size varies widely among members of the CaP clade (2.5-3.7 Mb), likely a result of independent genome reductions at each lineage. This includes a loss of tight adherence pilus genes (tad) in 'Ca. P. spiralis' that may reflect its adoption of a unique spiral cell shape and corkscrew-like burrowing activity at the algal surface. Notably, quorum sensing (QS) proteins showed incongruent phylogenies, suggesting that horizontal transfers of QS genes and QS-involved interactions with specific algal partners might drive CaP clade diversification. This study elucidates the ecophysiology and evolution of proteobacteria associated with freshwater algal blooms.
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Affiliation(s)
- Yuuhiko Tanabe
- Biodiversity Division, National Institute for Environmental Studies, Ibaraki, 305-8506, Japan.
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan.
| | - Haruyo Yamaguchi
- Biodiversity Division, National Institute for Environmental Studies, Ibaraki, 305-8506, Japan
| | - Masaki Yoshida
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Atsushi Kai
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Yusuke Okazaki
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
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8
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Tropodithietic Acid, a Multifunctional Antimicrobial, Facilitates Adaption and Colonization of the Producer, Phaeobacter piscinae. mSphere 2023; 8:e0051722. [PMID: 36622251 PMCID: PMC9942592 DOI: 10.1128/msphere.00517-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In the marine environment, surface-associated bacteria often produce an array of antimicrobial secondary metabolites, which have predominantly been perceived as competition molecules. However, they may also affect other hallmarks of surface-associated living, such as motility and biofilm formation. Here, we investigate the ecological significance of an antibiotic secondary metabolite, tropodithietic acid (TDA), in the producing bacterium, Phaeobacter piscinae S26. We constructed a markerless in-frame deletion mutant deficient in TDA biosynthesis, S26ΔtdaB. Molecular networking demonstrated that other chemical sulfur-containing features, likely related to TDA, were also altered in the secondary metabolome. We found several changes in the physiology of the TDA-deficient mutant, ΔtdaB, compared to the wild type. Growth of the two strains was similar; however, ΔtdaB cells were shorter and more motile. Transcriptome and proteome profiling revealed an increase in gene expression and protein abundance related to a type IV secretion system, and to a prophage, and a gene transfer agent in ΔtdaB. All these systems may contribute to horizontal gene transfer (HGT), which may facilitate adaptation to novel niches. We speculate that once a TDA-producing population has been established in a new niche, the accumulation of TDA acts as a signal of successful colonization, prompting a switch to a sessile lifestyle. This would lead to a decrease in motility and the rate of HGT, while filamentous cells could form the base of a biofilm. In addition, the antibiotic properties of TDA may inhibit invading competing microorganisms. This points to a role of TDA in coordinating colonization and adaptation. IMPORTANCE Despite the broad clinical usage of microbial secondary metabolites with antibiotic activity, little is known about their role in natural microbiomes. Here, we studied the effect of production of the antibiotic tropodithietic acid (TDA) on the producing strain, Phaeobacter piscinae S26, a member of the Roseobacter group. We show that TDA affects several phenotypes of the producing strain, including motility, cell morphology, metal metabolism, and three horizontal gene transfer systems: a prophage, a type IV secretion system, and a gene transfer agent. Together, this indicates that TDA participates in coordinating the colonization process of the producer. TDA is thus an example of a multifunctional secondary metabolite that can mediate complex interactions in microbial communities. This work broadens our understanding of the ecological role that secondary metabolites have in microbial community dynamics.
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Barak-Gavish N, Dassa B, Kuhlisch C, Nussbaum I, Brandis A, Rosenberg G, Avraham R, Vardi A. Bacterial lifestyle switch in response to algal metabolites. eLife 2023; 12:e84400. [PMID: 36691727 PMCID: PMC9873259 DOI: 10.7554/elife.84400] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/05/2023] [Indexed: 01/19/2023] Open
Abstract
Unicellular algae, termed phytoplankton, greatly impact the marine environment by serving as the basis of marine food webs and by playing central roles in the biogeochemical cycling of elements. The interactions between phytoplankton and heterotrophic bacteria affect the fitness of both partners. It is becoming increasingly recognized that metabolic exchange determines the nature of such interactions, but the underlying molecular mechanisms remain underexplored. Here, we investigated the molecular and metabolic basis for the bacterial lifestyle switch, from coexistence to pathogenicity, in Sulfitobacter D7 during its interaction with Emiliania huxleyi, a cosmopolitan bloom-forming phytoplankter. To unravel the bacterial lifestyle switch, we analyzed bacterial transcriptomes in response to exudates derived from algae in exponential growth and stationary phase, which supported the Sulfitobacter D7 coexistence and pathogenicity lifestyles, respectively. In pathogenic mode, Sulfitobacter D7 upregulated flagellar motility and diverse transport systems, presumably to maximize assimilation of E. huxleyi-derived metabolites released by algal cells upon cell death. Algal dimethylsulfoniopropionate (DMSP) was a pivotal signaling molecule that mediated the transition between the lifestyles, supporting our previous findings. However, the coexisting and pathogenic lifestyles were evident only in the presence of additional algal metabolites. Specifically, we discovered that algae-produced benzoate promoted the growth of Sulfitobacter D7 and hindered the DMSP-induced lifestyle switch to pathogenicity, demonstrating that benzoate is important for maintaining the coexistence of algae and bacteria. We propose that bacteria can sense the physiological state of the algal host through changes in the metabolic composition, which will determine the bacterial lifestyle during interaction.
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Affiliation(s)
- Noa Barak-Gavish
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Bareket Dassa
- Life Sciences Core Facilities, Weizmann Institute of ScienceRehovotIsrael
| | - Constanze Kuhlisch
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Inbal Nussbaum
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Alexander Brandis
- Life Sciences Core Facilities, Weizmann Institute of ScienceRehovotIsrael
| | - Gili Rosenberg
- Department of Biological Regulation, Weizmann Institute of ScienceRehovotIsrael
| | - Roi Avraham
- Department of Biological Regulation, Weizmann Institute of ScienceRehovotIsrael
| | - Assaf Vardi
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
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10
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Henriksen NNSE, Schostag MD, Balder SR, Bech PK, Strube ML, Sonnenschein EC, Gram L. The ability of Phaeobacter inhibens to produce tropodithietic acid influences the community dynamics of a microalgal microbiome. ISME COMMUNICATIONS 2022; 2:109. [PMID: 37938341 PMCID: PMC9723703 DOI: 10.1038/s43705-022-00193-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 10/14/2022] [Accepted: 10/19/2022] [Indexed: 11/09/2023]
Abstract
Microbial secondary metabolites facilitate microbial interactions and are crucial for understanding the complexity of microbial community dynamics. The purpose of the present study was to determine how a secondary metabolite producing marine bacteria or its metabolite deficient mutant affected the microbiome of the marine microalgae Tetraselmis suecica during a 70 day long co-evolution experiment. Using 16S rRNA gene amplicon sequencing, we found that neither the tropodithietic acid (TDA)-producing Phaeobacter inhibens wildtype nor the TDA-deficient mutant had major impacts on the community composition. However, a subset of strains, displayed temporally different relative abundance trajectories depending on the presence of P. inhibens. In particular, a Winogradskyella strain displayed temporal higher relative abundance when the TDA-producing wildtype was present. Numbers of the TDA-producing wildtype were reduced significantly more than those of the mutant over time indicating that TDA production was not an advantage. In communities without the P. inhibens wildtype strain, an indigenous population of Phaeobacter increased over time, indicating that indigenous Phaeobacter populations cannot co-exist with the TDA-producing wildtype. Despite that TDA was not detected chemically, we detected transcripts of the tdaC gene indicating that TDA could be produced in the microbial community associated with the algae. Our work highlights the importance of deciphering longitudinal strain dynamics when addressing the ecological effect of secondary metabolites in a relevant natural community.
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Affiliation(s)
| | - Morten Dencker Schostag
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads Bldg. 221, DK-2800 Kgs, Lyngby, Denmark
| | - Simone Rosen Balder
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads Bldg. 221, DK-2800 Kgs, Lyngby, Denmark
| | - Pernille Kjersgaard Bech
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads Bldg. 221, DK-2800 Kgs, Lyngby, Denmark
| | - Mikael Lenz Strube
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads Bldg. 221, DK-2800 Kgs, Lyngby, Denmark
| | - Eva Christina Sonnenschein
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads Bldg. 221, DK-2800 Kgs, Lyngby, Denmark
- Department of Biosciences, Swansea University, Singleton Park, SA2 8PP, Swansea, United Kingdom
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads Bldg. 221, DK-2800 Kgs, Lyngby, Denmark.
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11
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Bacterial Community Assembly, Succession, and Metabolic Function during Outdoor Cultivation of Microchloropsis salina. mSphere 2022; 7:e0023122. [PMID: 35730934 PMCID: PMC9429889 DOI: 10.1128/msphere.00231-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Outdoor cultivation of microalgae has promising potential for renewable bioenergy, but there is a knowledge gap on the structure and function of the algal microbiome that coinhabits these ecosystems. Here, we describe the assembly mechanisms, taxonomic structure, and metabolic potential of bacteria associated with Microchloropsis salina cultivated outdoors. Open mesocosms were inoculated with algal cultures that were either free of bacteria or coincubated with one of two different strains of alga-associated bacteria and were sampled across five time points taken over multiple harvesting rounds of a 40-day experiment. Using quantitative analyses of metagenome-assembled genomes (MAGs), we tracked bacterial community compositional abundance and taxon-specific functional capacity involved in algal-bacterial interactions. One of the inoculated bacteria (Alteromonas sp.) persisted and dispersed across mesocosms, whereas the other inoculated strain (Phaeobacter gallaeciensis) disappeared by day 17 while a taxonomically similar but functionally distinct Phaeobacter strain became established. The inoculated strains were less abundant than 6 numerically dominant newly recruited taxa with functional capacities for mutualistic or saprophytic lifestyles, suggesting a generalist approach to persistence. This includes a highly abundant unclassified Rhodobacteraceae species that fluctuated between 25% and 77% of the total community. Overall, we did not find evidence for priority effects exerted by the distinct inoculum conditions; all mesocosms converged with similar microbial community compositions by the end of the experiment. Instead, we infer that the 15 total populations were retained due to host selection, as they showed high metabolic potential for algal-bacterial interactions such as recycling alga-produced carbon and nitrogen and production of vitamins and secondary metabolites associated with algal growth and senescence, including B vitamins, tropodithietic acid, and roseobacticides. IMPORTANCE Bacteria proliferate in nutrient-rich aquatic environments, including engineered algal biofuel systems, where they remineralize photosynthates, exchange secondary metabolites with algae, and can influence system output of biomass or oil. Despite this, knowledge on the microbial ecology of algal cultivation systems is lacking, and the subject is worthy of investigation. Here, we used metagenomics to characterize the metabolic capacities of the predominant bacteria associated with the biofuel-relevant microalga Microchloropsis salina and to predict testable metabolic interactions between algae and manipulated communities of bacteria. We identified a previously undescribed and uncultivated organism that dominated the community. Collectively, the microbial community may interact with the alga in cultivation via exchange of secondary metabolites which could affect algal success, which we demonstrate as a possible outcome from controlled experiments with metabolically analogous isolates. These findings address the scalability of lab-based algal-bacterial interactions through to cultivation systems and more broadly provide a framework for empirical testing of genome-based metabolic predictions.
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12
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Zhang Y, Gallant É, Park JD, Seyedsayamdost MR. The Small-Molecule Language of Dynamic Microbial Interactions. Annu Rev Microbiol 2022; 76:641-660. [PMID: 35679616 PMCID: PMC10171915 DOI: 10.1146/annurev-micro-042722-091052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although microbes are routinely grown in monocultures in the laboratory, they are almost never encountered as single species in the wild. Our ability to detect and identify new microorganisms has advanced significantly in recent years, but our understanding of the mechanisms that mediate microbial interactions has lagged behind. What makes this task more challenging is that microbial alliances can be dynamic, consisting of multiple phases. The transitions between phases, and the interactions in general, are often mediated by a chemical language consisting of small molecules, also referred to as secondary metabolites or natural products. In this microbial lexicon, the molecules are like words and through their effects on recipient cells they convey meaning. The current review highlights three dynamic microbial interactions in which some of the words and their meanings have been characterized, especially those that mediate transitions in selected multiphasic associations. These systems provide insights into the principles that govern microbial symbioses and a playbook for interrogating similar associations in diverse ecological niches. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Yifan Zhang
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA; ,
| | - Étienne Gallant
- Department of Chemistry, Princeton University, Princeton, New Jersey, USA; ,
| | - Jong-Duk Park
- Department of Chemistry, Princeton University, Princeton, New Jersey, USA; ,
| | - Mohammad R Seyedsayamdost
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA; , .,Department of Chemistry, Princeton University, Princeton, New Jersey, USA; ,
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13
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Coyne KJ, Wang Y, Johnson G. Algicidal Bacteria: A Review of Current Knowledge and Applications to Control Harmful Algal Blooms. Front Microbiol 2022; 13:871177. [PMID: 35464927 PMCID: PMC9022068 DOI: 10.3389/fmicb.2022.871177] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/01/2022] [Indexed: 12/19/2022] Open
Abstract
Interactions between bacteria and phytoplankton in aqueous ecosystems are both complex and dynamic, with associations that range from mutualism to parasitism. This review focuses on algicidal interactions, in which bacteria are capable of controlling algal growth through physical association or the production of algicidal compounds. While there is some evidence for bacterial control of algal growth in the field, our understanding of these interactions is largely based on laboratory culture experiments. Here, the range of these algicidal interactions is discussed, including specificity of bacterial control, mechanisms for activity, and insights into the chemical and biochemical analysis of these interactions. The development of algicidal bacteria or compounds derived from bacteria for control of harmful algal blooms is reviewed with a focus on environmentally friendly or sustainable methods of application. Potential avenues for future research and further development and application of bacterial algicides for the control of algal blooms are presented.
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Affiliation(s)
- Kathryn J. Coyne
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE, United States
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14
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Roseobacter group probiotics exhibit differential killing of fish pathogenic Tenacibaculum species. Appl Environ Microbiol 2022; 88:e0241821. [PMID: 35080904 DOI: 10.1128/aem.02418-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fish pathogenic bacteria of the Tenacibaculum genus are a serious emerging concern in modern aquaculture, causing tenacibaculosis in a broad selection of cultured finfish. Data describing their virulence mechanisms are scarce and few means, antibiotic treatment aside, are available to control their proliferation in aquaculture systems. We genome sequenced a collection of 19 putative Tenacibaculum isolates from outbreaks at two aquaculture facilities and tested their susceptibility to treatment with tropodithietic acid (TDA)-producing Roseobacter group probiotics. We found that local outbreaks of Tenacibaculum can involve heterogeneous assemblages of species and strains with the capacity to produce multiple different virulence factors related to host invasion and infection. The probiotic Phaeobacter piscinae S26 proved efficient in killing pathogenic Tenacibaculum species such as T. maritimum, T. soleae, and some T. discolor strains. However, the T. mesophilum and T. gallaicum species exhibit natural tolerance towards TDA and are hence not likely to be easily killed by TDA-producing probiotics. Tolerance towards TDA in Tenacibaculum is likely involving multiple inherent physiological features pertaining to electron and proton transport, iron sequestration, and potentially also drug efflux mechanisms, as genetic determinants encoding such features were significantly associated with TDA tolerance. Collectively, our results support the use of TDA-producers to prevent tenacibaculosis, however, their efficacy is likely limited to some Tenacibaculum species. Importance A productive and sustainable aquaculture sector is needed to meet the UN sustainable development goals (SDGs) and supply the growing world population with high-protein food sources. A sustainable way to prevent disease outbreaks in the industry is the application of probiotic bacteria that can antagonize fish pathogens in the aquaculture systems. TDA-producing Roseobacter group probiotics have proven efficient in killing important vibrio pathogens and protecting fish larvae against infection, yet their efficacy against different fish pathogenic species of the Tenacibaculum genus has not been explored. Therefore, we tested the efficacy of such potential probiotics against a collection of different Tenacibaculum isolates and found the probiotic to efficiently kill a subset of relevant strains and species, supporting their use as sustainable disease control measure in aquaculture.
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15
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Henriksen NNSE, Lindqvist LL, Wibowo M, Sonnenschein EC, Bentzon-Tilia M, Gram L. OUP accepted manuscript. FEMS Microbiol Rev 2022; 46:6517774. [PMID: 35099011 PMCID: PMC9075582 DOI: 10.1093/femsre/fuac007] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Many microbial secondary metabolites have been studied for decades primarily because of their antimicrobial properties. However, several of these metabolites also possess nonantimicrobial functions, both influencing the physiology of the producer and their ecological neighbors. An example of a versatile bacterial secondary metabolite with multiple functions is the tropone derivative tropodithietic acid (TDA). TDA is a broad-spectrum antimicrobial compound produced by several members of the Rhodobacteraceae family, a major marine bacterial lineage, within the genera Phaeobacter, Tritonibacter, and Pseudovibrio. The production of TDA is governed by the mode of growth and influenced by the availability of nutrient sources. The antibacterial effect of TDA is caused by disruption of the proton motive force of target microorganisms and, potentially, by its iron-chelating properties. TDA also acts as a signaling molecule, affecting gene expression in other bacteria, and altering phenotypic traits such as motility, biofilm formation, and antibiotic production in the producer. In microbial communities, TDA-producing bacteria cause a reduction of the relative abundance of closely related species and some fast-growing heterotrophic bacteria. Here, we summarize the current understanding of the chemical ecology of TDA, including the environmental niches of TDA-producing bacteria, and the molecular mechanisms governing the function and regulation of TDA.
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Affiliation(s)
| | | | - Mario Wibowo
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
| | - Eva C Sonnenschein
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
| | - Mikkel Bentzon-Tilia
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
| | - Lone Gram
- Corresponding author: Department of Bioechnology and Biomedicine, Technical University of Denmark, Søltofts Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark. Tel: +45 23688295; E-mail:
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16
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Fenizia S, Weissflog J, Pohnert G. Cysteinolic Acid Is a Widely Distributed Compatible Solute of Marine Microalgae. Mar Drugs 2021; 19:md19120683. [PMID: 34940682 PMCID: PMC8703288 DOI: 10.3390/md19120683] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 11/23/2022] Open
Abstract
Phytoplankton rely on bioactive zwitterionic and highly polar small metabolites with osmoregulatory properties to compensate changes in the salinity of the surrounding seawater. Dimethylsulfoniopropionate (DMSP) is a main representative of this class of metabolites. Salinity-dependent DMSP biosynthesis and turnover contribute significantly to the global sulfur cycle. Using advanced chromatographic and mass spectrometric techniques that enable the detection of highly polar metabolites, we identified cysteinolic acid as an additional widely distributed polar metabolite in phytoplankton. Cysteinolic acid belongs to the class of marine sulfonates, metabolites that are commonly produced by algae and consumed by bacteria. It was detected in all dinoflagellates, haptophytes, diatoms and prymnesiophytes that were surveyed. We quantified the metabolite in different phytoplankton taxa and revealed that the cellular content can reach even higher concentrations than the ubiquitous DMSP. The cysteinolic acid concentration in the cells of the diatom Thalassiosira weissflogii increases significantly when grown in a medium with elevated salinity. In contrast to the compatible solute ectoine, cysteinolic acid is also found in high concentrations in axenic algae, indicating biosynthesis by the algae and not the associated bacteria. Therefore, we add this metabolite to the family of highly polar metabolites with osmoregulatory characteristics produced by phytoplankton.
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Affiliation(s)
- Simona Fenizia
- Bioorganic Analytics, Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstrasse 8, D-07743 Jena, Germany;
- MPG Fellow Group, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany;
| | - Jerrit Weissflog
- MPG Fellow Group, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany;
| | - Georg Pohnert
- Bioorganic Analytics, Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstrasse 8, D-07743 Jena, Germany;
- MPG Fellow Group, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany;
- Correspondence:
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17
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Wang R, Gallant É, Wilson MZ, Wu Y, Li A, Gitai Z, Seyedsayamdost MR. Algal p-coumaric acid induces oxidative stress and siderophore biosynthesis in the bacterial symbiont Phaeobacter inhibens. Cell Chem Biol 2021; 29:670-679.e5. [PMID: 34437838 DOI: 10.1016/j.chembiol.2021.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 06/18/2021] [Accepted: 08/06/2021] [Indexed: 11/28/2022]
Abstract
The marine alpha-proteobacterium Phaeobacter inhibens engages in intermittent symbioses with microalgae. The symbiosis is biphasic and concludes in a parasitic phase, during which the bacteria release algaecidal metabolites in response to algal p-coumaric acid (pCA). The cell-wide effects of pCA on P. inhibens remain unknown. Herein, we report a microarray-based transcriptomic study and find that genes related to the oxidative stress response and secondary metabolism are upregulated most, while those associated with energy production and motility are downregulated in the presence of pCA. Among genes upregulated is a previously unannotated biosynthetic gene cluster and, using a combination of gene deletions and metabolic profiling, we show that it gives rise to an unreported siderophore, roseobactin. The simultaneous production of algaecides and roseobactin in the parasitic phase allows the bacteria to take up any iron that is released from dying algal cells, thereby securing a limited micronutrient.
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Affiliation(s)
- Rurun Wang
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Étienne Gallant
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Maxwell Z Wilson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Yihan Wu
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Anran Li
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Mohammad R Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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18
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Duan Y, Toplak M, Hou A, Brock NL, Dickschat JS, Teufel R. A Flavoprotein Dioxygenase Steers Bacterial Tropone Biosynthesis via Coenzyme A-Ester Oxygenolysis and Ring Epoxidation. J Am Chem Soc 2021; 143:10413-10421. [PMID: 34196542 PMCID: PMC8283759 DOI: 10.1021/jacs.1c04996] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
Bacterial tropone
natural products such as tropolone, tropodithietic
acid, or the roseobacticides play crucial roles in various terrestrial
and marine symbiotic interactions as virulence factors, antibiotics,
algaecides, or quorum sensing signals. We now show that their poorly
understood biosynthesis depends on a shunt product from aerobic CoA-dependent
phenylacetic acid catabolism that is salvaged by the dedicated acyl-CoA
dehydrogenase-like flavoenzyme TdaE. Further characterization of TdaE
revealed an unanticipated complex catalysis, comprising substrate
dehydrogenation, noncanonical CoA-ester oxygenolysis, and final ring
epoxidation. The enzyme thereby functions as an archetypal flavoprotein
dioxygenase that incorporates both oxygen atoms from O2 into the substrate, most likely involving flavin-N5-peroxide and
flavin-N5-oxide species for consecutive CoA-ester cleavage and epoxidation,
respectively. The subsequent spontaneous decarboxylation of the reactive
enzyme product yields tropolone, which serves as a key virulence factor
in rice panicle blight caused by pathogenic edaphic Burkholderia
plantarii. Alternatively, the TdaE product is most likely
converted to more complex sulfur-containing secondary metabolites
such as tropodithietic acid from predominant marine Rhodobacteraceae (e.g., Phaeobacter inhibens).
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Affiliation(s)
- Ying Duan
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Marina Toplak
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Anwei Hou
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
| | - Nelson L Brock
- Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Jeroen S Dickschat
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.,Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Robin Teufel
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
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19
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Dow L. How Do Quorum-Sensing Signals Mediate Algae-Bacteria Interactions? Microorganisms 2021; 9:microorganisms9071391. [PMID: 34199114 PMCID: PMC8307130 DOI: 10.3390/microorganisms9071391] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/11/2021] [Accepted: 06/15/2021] [Indexed: 11/16/2022] Open
Abstract
Quorum sensing (QS) describes a process by which bacteria can sense the local cell density of their own species, thus enabling them to coordinate gene expression and physiological processes on a community-wide scale. Small molecules called autoinducers or QS signals, which act as intraspecies signals, mediate quorum sensing. As our knowledge of QS has progressed, so too has our understanding of the structural diversity of QS signals, along with the diversity of bacteria conducting QS and the range of ecosystems in which QS takes place. It is now also clear that QS signals are more than just intraspecies signals. QS signals mediate interactions between species of prokaryotes, and between prokaryotes and eukaryotes. In recent years, our understanding of QS signals as mediators of algae-bacteria interactions has advanced such that we are beginning to develop a mechanistic understanding of their effects. This review will summarize the recent efforts to understand how different classes of QS signals contribute to the interactions between planktonic microalgae and bacteria in our oceans, primarily N-acyl-homoserine lactones, their degradation products of tetramic acids, and 2-alkyl-4-quinolones. In particular, this review will discuss the ways in which QS signals alter microalgae growth and metabolism, namely as direct effectors of photosynthesis, regulators of the cell cycle, and as modulators of other algicidal mechanisms. Furthermore, the contribution of QS signals to nutrient acquisition is discussed, and finally, how microalgae can modulate these small molecules to dampen their effects.
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Affiliation(s)
- Lachlan Dow
- Root Microbe Interactions Laboratory, Australian National University, Canberra 0200, Australia
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20
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Holomycin, an Antibiotic Secondary Metabolite, Is Required for Biofilm Formation by the Native Producer Photobacterium galatheae S2753. Appl Environ Microbiol 2021; 87:AEM.00169-21. [PMID: 33771780 DOI: 10.1128/aem.00169-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/18/2021] [Indexed: 01/24/2023] Open
Abstract
While the effects of antibiotics on microorganisms are widely studied, it remains less well understood how antibiotics affect the physiology of the native producing organisms. Here, using a marine bacterium, Photobacterium galatheae S2753, that produces the antibiotic holomycin, we generated a holomycin-deficient strain by in-frame deletion of hlmE, the core gene responsible for holomycin production. Mass spectrometry analysis of cell extracts confirmed that the ΔhlmE strain did not produce holomycin and that the mutant was devoid of antibacterial activity. Biofilm formation of the ΔhlmE strain was significantly reduced compared to that of wild-type S2753 and was restored in an hlmE complementary mutant. Consistent with this, exogenous holomycin, but not its dimethylated and less antibacterial derivative, S,S'-dimethyl holomycin, restored the biofilm formation of the ΔhlmE strain. Furthermore, zinc starvation was found to be essential for both holomycin production and biofilm formation of S2753, although the molecular mechanism remains elusive. Collectively, these data suggest that holomycin promotes biofilm formation of S2753 via its ene-disulfide group. Lastly, the addition of holomycin at subinhibitory concentrations also enhanced the biofilms of four other Vibrionaceae strains. P. galatheae likely gains an ecological advantage from producing holomycin as both an antibiotic and a biofilm stimulator, which facilitates nutrition acquisition and protects P. galatheae from environmental stresses. Studying the function of antibiotic compounds in the native producer will shed light on their roles in nature and could point to novel bioprospecting strategies.IMPORTANCE Despite the societal impact of antibiotics, their ecological functions remain elusive and have mostly been studied by exposing nonproducing bacteria to subinhibitory concentrations. Here, we studied the effects of the antibiotic holomycin on its native producer, Photobacterium galatheae S2753, a Vibrionaceae bacterium. Holomycin provides a distinct advantage to S2753 both as an antibiotic and by enhancing biofilm formation in the producer. Vibrionaceae species successfully thrive in global marine ecosystems, where they play critical ecological roles as free-living, symbiotic, or pathogenic bacteria. Genome mining has demonstrated that many have the potential to produce several bioactive compounds, including P. galatheae To unravel the contribution of the microbial metabolites to the development of marine microbial ecosystems, better insight into the function of these compounds in the producing organisms is needed. Our finding provides a model to pursue this and highlights the ecological importance of antibiotics to the fitness of the producing organisms.
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21
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The Roseobacter-Group Bacterium Phaeobacter as a Safe Probiotic Solution for Aquaculture. Appl Environ Microbiol 2021; 87:e0258120. [PMID: 33310713 DOI: 10.1128/aem.02581-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phaeobacter inhibens has been assessed as a probiotic bacterium for application in aquaculture. Studies addressing the efficacy and safety indicate that P. inhibens maintains its antagonistic activity against pathogenic vibrios in aquaculture live cultures (live feed and fish egg/larvae) while having no or a positive effect on the host organisms and a minor impact on the host microbiomes. While P. inhibens produces antibacterial and algicidal compounds, no study has so far found a virulent phenotype of P. inhibens cells against higher organisms. Additionally, an in silico search for antibiotic resistance genes using published genomes of representative strains did not raise concerns regarding the risk for antimicrobial resistance. P. inhibens occurs naturally in aquaculture systems, supporting its safe usage in this environment. In conclusion, at the current state of knowledge, P. inhibens is a "safe-to-use" organism.
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22
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Moffat AD, Elliston A, Patron NJ, Truman AW, Carrasco Lopez JA. A biofoundry workflow for the identification of genetic determinants of microbial growth inhibition. Synth Biol (Oxf) 2021; 6:ysab004. [PMID: 33623825 PMCID: PMC7889406 DOI: 10.1093/synbio/ysab004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/04/2021] [Accepted: 01/12/2021] [Indexed: 11/20/2022] Open
Abstract
Biofoundries integrate high-throughput software and hardware platforms with synthetic biology approaches to enable the design, execution and analyses of large-scale experiments. The unique and powerful combination of laboratory infrastructure and expertise in molecular biology and automation programming, provide flexible resources for a wide range of workflows and research areas. Here, we demonstrate the applicability of biofoundries to molecular microbiology, describing the development and application of automated workflows to identify the genetic basis of growth inhibition of the plant pathogen Streptomyces scabies by a Pseudomonas strain isolated from a potato field. Combining transposon mutagenesis with automated high-throughput antagonistic assays, the workflow accelerated the screening of 2880 mutants to correlate growth inhibition with a biosynthetic gene cluster within 2 weeks.
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Affiliation(s)
- Alaster D Moffat
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, UK
| | - Adam Elliston
- Department of Engineering Biology, Earlham Institute, Norwich Research Park, Norwich, UK
| | - Nicola J Patron
- Department of Engineering Biology, Earlham Institute, Norwich Research Park, Norwich, UK
| | - Andrew W Truman
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, UK
| | - Jose A Carrasco Lopez
- Department of Engineering Biology, Earlham Institute, Norwich Research Park, Norwich, UK
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23
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Discovering the Molecular Determinants of Phaeobacter inhibens Susceptibility to Phaeobacter Phage MD18. mSphere 2020; 5:5/6/e00898-20. [PMID: 33148823 PMCID: PMC7643831 DOI: 10.1128/msphere.00898-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Bacteriophages have immense potential as antibiotic therapies and in genetic engineering. Understanding the mechanisms that bacteriophages implement to infect their hosts will allow researchers to manipulate these systems and adapt them to specific bacterial targets. In this study, we isolated a bacteriophage capable of infecting the marine alphaproteobacterium Phaeobacter inhibens and determined its mechanism of infection. Phaeobacter virus MD18, a novel species of bacteriophage isolated in Woods Hole, MA, exhibits potent lytic ability against P. inhibens and appears to be of the Siphoviridae morphotype. The genomic sequence of MD18 displayed significant similarity to another siphophage, the recently discovered Roseobacter phage DSS3P8, but genomic and phylogenetic analyses, assessing host range and a search of available metagenomes are all consistent with the conclusion that Phaeobacter phage MD18 is a novel lytic phage. We incubated MD18 with a library of barcoded P. inhibens transposon insertion mutants and identified 22 genes that appear to be required for phage predation of this host. Network analysis of these genes using genomic position, Gene Ontology (GO) term enrichment, and protein associations revealed that these genes are enriched for roles in assembly of a type IV pilus (T4P) and regulators of cellular morphology. Our results suggest that T4P serve as receptors for a novel marine virus that targets P. inhibens. IMPORTANCE Bacteriophages are useful nonantibiotic therapeutics for bacterial infections as well as threats to industries utilizing bacterial agents. This study identified Phaeobacter virus MD18, a phage antagonist of Phaeobacter inhibens, a bacterium with promising use as a probiotic for aquatic farming industries. Genomic analysis suggested that Phaeobacter phage MD18 has evolved to enhance its replication in P. inhibens by adopting favorable tRNA genes as well as through genomic sequence adaptation to resemble host codon usage. Lastly, a high-throughput analysis of P. inhibens transposon insertion mutants identified genes that modulate host susceptibility to phage MD18 and implicated the type IV pilus as the likely receptor recognized for adsorption. This study marks the first characterization of the relationship between P. inhibens and an environmentally sampled phage, which informs our understanding of natural threats to the bacterium and may promote the development of novel phage technologies for genetic manipulation of this host.
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Duan Y, Petzold M, Saleem‐Batcha R, Teufel R. Bacterial Tropone Natural Products and Derivatives: Overview of their Biosynthesis, Bioactivities, Ecological Role and Biotechnological Potential. Chembiochem 2020; 21:2384-2407. [PMID: 32239689 PMCID: PMC7497051 DOI: 10.1002/cbic.201900786] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 04/02/2020] [Indexed: 12/05/2022]
Abstract
Tropone natural products are non-benzene aromatic compounds of significant ecological and pharmaceutical interest. Herein, we highlight current knowledge on bacterial tropones and their derivatives such as tropolones, tropodithietic acid, and roseobacticides. Their unusual biosynthesis depends on a universal CoA-bound precursor featuring a seven-membered carbon ring as backbone, which is generated by a side reaction of the phenylacetic acid catabolic pathway. Enzymes encoded by separate gene clusters then further modify this key intermediate by oxidation, CoA-release, or incorporation of sulfur among other reactions. Tropones play important roles in the terrestrial and marine environment where they act as antibiotics, algaecides, or quorum sensing signals, while their bacterial producers are often involved in symbiotic interactions with plants and marine invertebrates (e. g., algae, corals, sponges, or mollusks). Because of their potent bioactivities and of slowly developing bacterial resistance, tropones and their derivatives hold great promise for biomedical or biotechnological applications, for instance as antibiotics in (shell)fish aquaculture.
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Affiliation(s)
- Ying Duan
- Faculty of BiologyUniversity of Freiburg79104FreiburgGermany
| | - Melanie Petzold
- Faculty of BiologyUniversity of Freiburg79104FreiburgGermany
| | | | - Robin Teufel
- Faculty of BiologyUniversity of Freiburg79104FreiburgGermany
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25
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Fukuda TTH, Cassilly CD, Gerdt JP, Henke MT, Helfrich EJN, Mevers E. Research Tales from the Clardy Laboratory: Function-Driven Natural Product Discovery. JOURNAL OF NATURAL PRODUCTS 2020; 83:744-755. [PMID: 32105475 DOI: 10.1021/acs.jnatprod.9b01086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Over the past 70 years, the search for small molecules from nature has transformed biomedical research: natural products are the basis for half of all pharmaceuticals; the quest for total synthesis of natural products fueled development of methodologies for organic synthesis; and their biosynthesis presented unprecedented biochemical transformations, expanding our chemo-enzymatic toolkit. Initially, the discovery of small molecules was driven by bioactivity-guided fractionation. However, this approach yielded the frequent rediscovery of already known metabolites. As a result, focus shifted to identifying novel scaffolds through either structure-first methods or genome mining, relegating function as a secondary concern. Over the past two decades, the laboratory of Jon Clardy has taken an alternative route and focused on an ecology-driven, function-first approach in pursuit of uncovering bacterial small molecules with biological activity. In this review, we highlight several examples that showcase this ecology-first approach. Though the highlighted systems are diverse, unifying themes are (1) to understand how microbes interact with their host or environment, (2) to gain insights into the environmental roles of microbial metabolites, and (3) to explore pharmaceutical potential from these ecologically relevant metabolites.
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Affiliation(s)
- Taise T H Fukuda
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, 14040-903, Ribeirão Preto, SP, Brazil
| | - Chelsi D Cassilly
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Joseph P Gerdt
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Matthew T Henke
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Eric J N Helfrich
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Emily Mevers
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
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Muzio FM, Agaras BC, Masi M, Tuzi A, Evidente A, Valverde C. 7‐hydroxytropolone is the main metabolite responsible for the fungal antagonism of
Pseudomonas donghuensis
strain SVBP6. Environ Microbiol 2020; 22:2550-2563. [DOI: 10.1111/1462-2920.14925] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/06/2020] [Accepted: 01/23/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Federico M. Muzio
- Laboratorio de Fisiología y Genética de Bacterias Beneficiosas para Plantas—Centro de Bioquímica y Microbiología del Suelo. Departamento de Ciencia y TecnologíaUniversidad Nacional de Quilmes—CONICET, Roque Sáenz Peña 352, Bernal B1876BXD Buenos Aires Argentina
| | - Betina C. Agaras
- Laboratorio de Fisiología y Genética de Bacterias Beneficiosas para Plantas—Centro de Bioquímica y Microbiología del Suelo. Departamento de Ciencia y TecnologíaUniversidad Nacional de Quilmes—CONICET, Roque Sáenz Peña 352, Bernal B1876BXD Buenos Aires Argentina
| | - Marco Masi
- Dipartimento di Scienze Chimiche, Università di Napoli “Federico II”Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Naples Italy
| | - Angela Tuzi
- Dipartimento di Scienze Chimiche, Università di Napoli “Federico II”Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Naples Italy
| | - Antonio Evidente
- Dipartimento di Scienze Chimiche, Università di Napoli “Federico II”Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Naples Italy
| | - Claudio Valverde
- Laboratorio de Fisiología y Genética de Bacterias Beneficiosas para Plantas—Centro de Bioquímica y Microbiología del Suelo. Departamento de Ciencia y TecnologíaUniversidad Nacional de Quilmes—CONICET, Roque Sáenz Peña 352, Bernal B1876BXD Buenos Aires Argentina
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Spieker M, Saleem-Batcha R, Teufel R. Structural and Mechanistic Basis of an Oxepin-CoA Forming Isomerase in Bacterial Primary and Secondary Metabolism. ACS Chem Biol 2019; 14:2876-2886. [PMID: 31689071 DOI: 10.1021/acschembio.9b00742] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Numerous aromatic compounds are aerobically degraded in bacteria via the central intermediate phenylacetic acid (paa). In one of the key steps of this widespread catabolic pathway, 1,2-epoxyphenylacetyl-CoA is converted by PaaG into the heterocyclic oxepin-CoA. PaaG thereby elegantly generates an α,β-unsaturated CoA ester that is predisposed to undergo β-oxidation subsequent to hydrolytic ring-cleavage. Moreover, oxepin-CoA serves as a precursor for secondary metabolites (e.g., tropodithietic acid) that act as antibiotics and quorum-sensing signals. Here we verify that PaaG adopts a second role in aromatic catabolism by converting cis-3,4-didehydroadipoyl-CoA into trans-2,3-didehydroadipoyl-CoA and corroborate a Δ3,Δ2-enoyl-CoA isomerase-like proton shuttling mechanism for both distinct substrates. Biochemical and structural investigations of PaaG reveal active site adaptations to the structurally different substrates and provide detailed insight into catalysis and control of stereospecificity. This work elucidates the mechanism of action of unusual isomerase PaaG and sheds new light on the ubiquitous enoyl-CoA isomerases of the crotonase superfamily.
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Affiliation(s)
- Melanie Spieker
- ZBSA, Center for Biological Systems Analysis, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Raspudin Saleem-Batcha
- ZBSA, Center for Biological Systems Analysis, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Robin Teufel
- ZBSA, Center for Biological Systems Analysis, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
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28
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Rambo IM, Dombrowski N, Constant L, Erdner D, Baker BJ. Metabolic relationships of uncultured bacteria associated with the microalgae Gambierdiscus. Environ Microbiol 2019; 22:1764-1783. [PMID: 31775181 DOI: 10.1111/1462-2920.14878] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 11/13/2019] [Accepted: 11/25/2019] [Indexed: 12/14/2022]
Abstract
Microbial communities inhabit algae cell surfaces and produce a variety of compounds that can impact the fitness of the host. These interactions have been studied via culturing, single-gene diversity and metagenomic read survey methods that are limited by culturing biases and fragmented genetic characterizations. Higher-resolution frameworks are needed to resolve the physiological interactions within these algal-bacterial communities. Here, we infer the encoded metabolic capabilities of four uncultured bacterial genomes (reconstructed using metagenomic assembly and binning) associated with the marine dinoflagellates Gambierdiscus carolinianus and G. caribaeus. Phylogenetic analyses revealed that two of the genomes belong to the commonly algae-associated families Rhodobacteraceae and Flavobacteriaceae. The other two genomes belong to the Phycisphaeraceae and include the first algae-associated representative within the uncultured SM1A02 group. Analyses of all four genomes suggest these bacteria are facultative aerobes, with some capable of metabolizing phytoplanktonic organosulfur compounds including dimethylsulfoniopropionate and sulfated polysaccharides. These communities may biosynthesize compounds beneficial to both the algal host and other bacteria, including iron chelators, B vitamins, methionine, lycopene, squalene and polyketides. These findings have implications for marine carbon and nutrient cycling and provide a greater depth of understanding regarding the genetic potential for complex physiological interactions between microalgae and their associated bacteria.
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Affiliation(s)
- Ian M Rambo
- Department of Marine Science, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX, 78373, USA
| | - Nina Dombrowski
- Department of Marine Science, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX, 78373, USA.,NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, Den Burg, The Netherlands
| | - Lauren Constant
- Department of Marine Science, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX, 78373, USA
| | - Deana Erdner
- Department of Marine Science, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX, 78373, USA
| | - Brett J Baker
- Department of Marine Science, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX, 78373, USA
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29
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Amino Acid and Sugar Catabolism in the Marine Bacterium Phaeobacter inhibens DSM 17395 from an Energetic Viewpoint. Appl Environ Microbiol 2019; 85:AEM.02095-19. [PMID: 31604772 DOI: 10.1128/aem.02095-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/07/2019] [Indexed: 11/20/2022] Open
Abstract
Growth energetics and metabolic efficiency contribute to the lifestyle and habitat imprint of microorganisms. Roseobacters constitute one of the most abundant and successful marine bacterioplankton groups. Here, we reflect on the energetics and metabolic efficiency of Phaeobacter inhibens DSM 17395, a versatile heterotrophic roseobacter. Fourteen different substrates (five sugars and nine amino acids) and their degradation pathways were assessed for energetic efficiencies based on catabolic ATP yields, calculated from net formed ATP and reducing equivalents. The latter were converted into ATP by employing the most divergent coupling ratios (i.e., ions per ATP) currently known for F1Fo ATP synthases in heterotrophic bacteria. The catabolic ATP yields of the pathways studied in P. inhibens differed ∼3-fold. The actual free energy costs for ATP synthesis were estimated at 81.6 kJ per mol ATP (3.3 ions per ATP) or 104.2 kJ per mol ATP (4.3 ions per ATP), yielding an average thermodynamic efficiency of ∼37.7% or ∼29.5%, respectively. Growth performance (rates, yields) and carbon assimilation efficiency were determined for P. inhibens growing in process-controlled bioreactors with 10 different single substrates (Glc, Man, N-acetylglucosamine [Nag], Phe, Trp, His, Lys, Thr, Val, or Leu) and with 2 defined substrate mixtures. The efficiencies of carbon assimilation into biomass ranged from ∼28% to 61%, with His/Trp and Thr/Leu yielding the lowest and highest levels. These efficiencies correlated with catabolic and ATP yields only to some extent. Substrate-specific metabolic demands and/or functions, as well as the compositions of the substrate mixtures, apparently affected the energetic costs of growth. These include energetic burdens associated with, e.g., slow growth, stress, and/or the production of tropodithietic acid.IMPORTANCE Heterotrophic members of the bacterioplankton serve the marine ecosystem by transforming organic matter, an activity that is governed by the bacterial growth efficiencies (BGEs) obtained under given environmental conditions. In marine ecology, the concept of BGE refers to the carbon assimilation efficiency within natural communities. The marine bacterium studied here, Phaeobacter inhibens DSM 17395, is a copiotrophic representative of the globally abundant Roseobacter group, and the 15 catabolic pathways investigated are widespread among these marine heterotrophs. Combining pathway-specific catabolic ATP yields with in-depth quantitative physiological data could (i) provide a new baseline for the study of growth energetics and efficiency in further Roseobacter group members and other copiotrophic marine bacteria in productive coastal ecosystems and (ii) contribute to a better understanding of the factors controlling BGE (including the additional energetic burden arising from widespread secondary-metabolite formation) based on laboratory studies with pure cultures.
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30
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Phippen CBW, Jørgensen CM, Bentzon-Tilia M, Gotfredsen CH, Larsen TO, Gram L, Sonnenschein EC. Isolation of Methyl Troposulfenin from Phaeobacter inhibens. JOURNAL OF NATURAL PRODUCTS 2019; 82:1387-1390. [PMID: 30978024 DOI: 10.1021/acs.jnatprod.8b01097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
An S-methylated analogue of tropodithietic acid (TDA, 1), methyl troposulfenin (2), was isolated from the marine alphaproteobacterium Phaeobacter inhibens. The structure was elucidated by NMR and HRMS. Its inhibitory effect against the fish pathogen Vibrio anguillarum was 4-fold to 100-fold lower than that of the known antibacterial compound TDA. Methyl troposulfenin lacks the acidic proton of TDA, indicating that the methylation turns the potent antibacterial TDA into an inactive compound, and thereby, this analysis supports the proposed mode of action of TDA.
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Affiliation(s)
- Christopher B W Phippen
- Department of Biotechnology and Biomedicine , Technical University of Denmark , Søltofts Plads 221 , Kongens Lyngby , 2800 , Denmark
| | - Cecilie M Jørgensen
- Department of Biotechnology and Biomedicine , Technical University of Denmark , Søltofts Plads 221 , Kongens Lyngby , 2800 , Denmark
| | - Mikkel Bentzon-Tilia
- Department of Biotechnology and Biomedicine , Technical University of Denmark , Søltofts Plads 221 , Kongens Lyngby , 2800 , Denmark
| | - Charlotte Held Gotfredsen
- Department of Chemistry , Technical University of Denmark , Kemitorvet 207 , Kongens Lyngby , 2800 , Denmark
| | - Thomas O Larsen
- Department of Biotechnology and Biomedicine , Technical University of Denmark , Søltofts Plads 221 , Kongens Lyngby , 2800 , Denmark
| | - Lone Gram
- Department of Biotechnology and Biomedicine , Technical University of Denmark , Søltofts Plads 221 , Kongens Lyngby , 2800 , Denmark
| | - Eva C Sonnenschein
- Department of Biotechnology and Biomedicine , Technical University of Denmark , Søltofts Plads 221 , Kongens Lyngby , 2800 , Denmark
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31
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Brown ER, Cepeda MR, Mascuch SJ, Poulson-Ellestad KL, Kubanek J. Chemical ecology of the marine plankton. Nat Prod Rep 2019; 36:1093-1116. [DOI: 10.1039/c8np00085a] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A review of chemically mediated interactions in planktonic marine environments covering new studies from January 2015 to December 2017.
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Affiliation(s)
- Emily R. Brown
- School of Biological Sciences
- Aquatic Chemical Ecology Center
- Institute for Bioengineering and Biosciences
- Georgia Institute of Technology
- Atlanta
| | - Marisa R. Cepeda
- School of Chemistry and Biochemistry
- Aquatic Chemical Ecology Center
- Institute for Bioengineering and Biosciences
- Georgia Institute of Technology
- Atlanta
| | - Samantha J. Mascuch
- School of Biological Sciences
- Aquatic Chemical Ecology Center
- Institute for Bioengineering and Biosciences
- Georgia Institute of Technology
- Atlanta
| | | | - Julia Kubanek
- School of Biological Sciences
- Aquatic Chemical Ecology Center
- Institute for Bioengineering and Biosciences
- Georgia Institute of Technology
- Atlanta
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32
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Calero P, Nikel PI. Chasing bacterial chassis for metabolic engineering: a perspective review from classical to non-traditional microorganisms. Microb Biotechnol 2019; 12:98-124. [PMID: 29926529 PMCID: PMC6302729 DOI: 10.1111/1751-7915.13292] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 12/27/2022] Open
Abstract
The last few years have witnessed an unprecedented increase in the number of novel bacterial species that hold potential to be used for metabolic engineering. Historically, however, only a handful of bacteria have attained the acceptance and widespread use that are needed to fulfil the needs of industrial bioproduction - and only for the synthesis of very few, structurally simple compounds. One of the reasons for this unfortunate circumstance has been the dearth of tools for targeted genome engineering of bacterial chassis, and, nowadays, synthetic biology is significantly helping to bridge such knowledge gap. Against this background, in this review, we discuss the state of the art in the rational design and construction of robust bacterial chassis for metabolic engineering, presenting key examples of bacterial species that have secured a place in industrial bioproduction. The emergence of novel bacterial chassis is also considered at the light of the unique properties of their physiology and metabolism, and the practical applications in which they are expected to outperform other microbial platforms. Emerging opportunities, essential strategies to enable successful development of industrial phenotypes, and major challenges in the field of bacterial chassis development are also discussed, outlining the solutions that contemporary synthetic biology-guided metabolic engineering offers to tackle these issues.
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Affiliation(s)
- Patricia Calero
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark2800Kongens LyngbyDenmark
| | - Pablo I. Nikel
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark2800Kongens LyngbyDenmark
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Barak-Gavish N, Frada MJ, Ku C, Lee PA, DiTullio GR, Malitsky S, Aharoni A, Green SJ, Rotkopf R, Kartvelishvily E, Sheyn U, Schatz D, Vardi A. Bacterial virulence against an oceanic bloom-forming phytoplankter is mediated by algal DMSP. SCIENCE ADVANCES 2018; 4:eaau5716. [PMID: 30397652 PMCID: PMC6200362 DOI: 10.1126/sciadv.aau5716] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/17/2018] [Indexed: 05/12/2023]
Abstract
Emiliania huxleyi is a bloom-forming microalga that affects the global sulfur cycle by producing large amounts of dimethylsulfoniopropionate (DMSP) and its volatile metabolic product dimethyl sulfide. Top-down regulation of E. huxleyi blooms has been attributed to viruses and grazers; however, the possible involvement of algicidal bacteria in bloom demise has remained elusive. We demonstrate that a Roseobacter strain, Sulfitobacter D7, that we isolated from a North Atlantic E. huxleyi bloom, exhibited algicidal effects against E. huxleyi upon coculturing. Both the alga and the bacterium were found to co-occur during a natural E. huxleyi bloom, therefore establishing this host-pathogen system as an attractive, ecologically relevant model for studying algal-bacterial interactions in the oceans. During interaction, Sulfitobacter D7 consumed and metabolized algal DMSP to produce high amounts of methanethiol, an alternative product of DMSP catabolism. We revealed a unique strain-specific response, in which E. huxleyi strains that exuded higher amounts of DMSP were more susceptible to Sulfitobacter D7 infection. Intriguingly, exogenous application of DMSP enhanced bacterial virulence and induced susceptibility in an algal strain typically resistant to the bacterial pathogen. This enhanced virulence was highly specific to DMSP compared to addition of propionate and glycerol which had no effect on bacterial virulence. We propose a novel function for DMSP, in addition to its central role in mutualistic interactions among marine organisms, as a mediator of bacterial virulence that may regulate E. huxleyi blooms.
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Affiliation(s)
- Noa Barak-Gavish
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Miguel José Frada
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
- The Interuniversity Institute for Marine Sciences, Eilat 88103, Israel
- Department of Ecology, Evolution and Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Chuan Ku
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Peter A. Lee
- Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412, USA
| | - Giacomo R. DiTullio
- Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412, USA
| | - Sergey Malitsky
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Biological Services, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Asaph Aharoni
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Stefan J. Green
- DNA Services Facility, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Ron Rotkopf
- Department of Biological Services, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Elena Kartvelishvily
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Uri Sheyn
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Daniella Schatz
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Assaf Vardi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
- Corresponding author.
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Role of Chemical Mediators in Aquatic Interactions across the Prokaryote-Eukaryote Boundary. J Chem Ecol 2018; 44:1008-1021. [PMID: 30105643 DOI: 10.1007/s10886-018-1004-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 07/24/2018] [Accepted: 07/30/2018] [Indexed: 10/28/2022]
Abstract
There is worldwide growing interest in the occurrence and diversity of metabolites used as chemical mediators in cross-kingdom interactions within aquatic systems. Bacteria produce metabolites to protect and influence the growth and life cycle of their eukaryotic hosts. In turn, the host provides a nutrient-enriched environment for the bacteria. Here, we discuss the role of waterborne chemical mediators that are responsible for such interactions in aquatic multi-partner systems, including algae or invertebrates and their associated bacteria. In particular, this review highlights recent advances in the chemical ecology of aquatic systems that support the overall ecological significance of signaling molecules across the prokaryote-eukaryote boundary (cross-kingdom interactions) for growth, development and morphogenesis of the host. We emphasize the value of establishing well-characterized model systems that provide the basis for the development of ecological principles that represent the natural lifestyle and dynamics of aquatic microbial communities and enable a better understanding of the consequences of environmental change and the most effective means of managing community interactions.
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35
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Guidi F, Pezzolesi L, Vanucci S. Microbial dynamics during harmful dinoflagellate Ostreopsis cf. ovata growth: Bacterial succession and viral abundance pattern. Microbiologyopen 2018; 7:e00584. [PMID: 29484854 PMCID: PMC6079179 DOI: 10.1002/mbo3.584] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 12/13/2017] [Accepted: 12/19/2017] [Indexed: 12/13/2022] Open
Abstract
Algal-bacterial interactions play a major role in shaping diversity of algal associated bacterial communities. Temporal variation in bacterial phylogenetic composition reflects changes of these complex interactions which occur during the algal growth cycle as well as throughout the lifetime of algal blooms. Viruses are also known to cause shifts in bacterial community diversity which could affect algal bloom phases. This study investigated on changes of bacterial and viral abundances, bacterial physiological status, and on bacterial successional pattern associated with the harmful benthic dinoflagellate Ostreopsis cf. ovata in batch cultures over the algal growth cycle. Bacterial community phylogenetic structure was assessed by 16S rRNA gene ION torrent sequencing. A comparison between bacterial community retrieved in cultures and that one co-occurring in situ during the development of the O. cf. ovata bloom from where the algal strain was isolated was also reported. Bacterial community growth was characterized by a biphasic pattern with the highest contributions (~60%) of highly active bacteria found at the two bacterial exponential growth steps. An alphaproteobacterial consortium composed by the Rhodobacteraceae Dinoroseobacter (22.2%-35.4%) and Roseovarius (5.7%-18.3%), together with Oceanicaulis (14.2-40.3%), was strongly associated with O. cf. ovata over the algal growth. The Rhodobacteraceae members encompassed phylotypes with an assessed mutualistic-pathogenic bimodal behavior. Fabibacter (0.7%-25.2%), Labrenzia (5.6%-24.3%), and Dietzia (0.04%-1.7%) were relevant at the stationary phase. Overall, the successional pattern and the metabolic and functional traits of the bacterial community retrieved in culture mirror those ones underpinning O. cf. ovata bloom dynamics in field. Viral abundances increased synoptically with bacterial abundances during the first bacterial exponential growth step while being stationary during the second step. Microbial trends also suggest that viruses induced some shifts in bacterial community composition.
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Affiliation(s)
- Flavio Guidi
- Department of Biological, Geological and Environmental Sciences (BiGeA)University of BolognaRavennaItaly
| | - Laura Pezzolesi
- Department of Biological, Geological and Environmental Sciences (BiGeA)University of BolognaRavennaItaly
| | - Silvana Vanucci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (ChiBioFarAm)University of MessinaMessinaItaly
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Thøgersen MS, Melchiorsen J, Ingham C, Gram L. A Novel Microbial Culture Chamber Co-cultivation System to Study Algal-Bacteria Interactions Using Emiliania huxleyi and Phaeobacter inhibens as Model Organisms. Front Microbiol 2018; 9:1705. [PMID: 30105010 PMCID: PMC6077189 DOI: 10.3389/fmicb.2018.01705] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 07/09/2018] [Indexed: 02/03/2023] Open
Abstract
Our understanding of microbial natural environments combines in situ experimentation with studies of specific interactions in laboratory-based setups. The purpose of this work was to develop, build and demonstrate the use of a microbial culture chamber enabling both in situ and laboratory-based studies. The design uses an enclosed chamber surrounded by two porous membranes that enables the comparison of growth of two separate microbial populations but allowing free exchange of small molecules. Initially, we tested if the presence of the macroalga Fucus vesiculosus inside the chamber affected colonization of the outer membranes by marine bacteria. The alga did indeed enrich the total population of colonizing bacteria by more than a factor of four. These findings lead us to investigate the effect of the presence of the coccolithophoric alga Emiliania huxleyi on attachment and biofilm formation of the marine bacterium Phaeobacter inhibens DSM17395. These organisms co-exist in the marine environment and have a well-characterized interdependence on secondary metabolites. P. inhibens attached in significantly higher numbers when having access to E. huxleyi as compared to when exposed to sterile media. The experiment was carried out using a wild type (wt) strain as well as a TDA-deficient strain of P. inhibens. The ability of the bacterium to produce the antibacterial compound, tropodithietic acid (TDA) influenced its attachment since the P. inhibens DSM17395 wt strain attached in higher numbers to a surface within the first 48 h of incubation with E. huxleyi as compared to a TDA-negative mutant. Whilst the attachment of the bacterium to a surface was facilitated by presence of the alga, however, we cannot conclude if this was directly affected by the algae or whether biofilm formation was dependent on the production of TDA by P. inhibens, which has been implied by previous studies. In the light of these results, other applications of immersed culture chambers are suggested.
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Affiliation(s)
- Mariane S Thøgersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jette Melchiorsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
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37
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Lian J, Wijffels RH, Smidt H, Sipkema D. The effect of the algal microbiome on industrial production of microalgae. Microb Biotechnol 2018; 11:806-818. [PMID: 29978601 PMCID: PMC6116740 DOI: 10.1111/1751-7915.13296] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 06/10/2018] [Accepted: 06/11/2018] [Indexed: 12/22/2022] Open
Abstract
Microbes are ubiquitously distributed, and they are also present in algae production systems. The algal microbiome is a pivotal part of the alga holobiont and has a key role in modulating algal populations in nature. However, there is a lack of knowledge on the role of bacteria in artificial systems ranging from laboratory flasks to industrial ponds. Coexisting microorganisms, and predominantly bacteria, are often regarded as contaminants in algal research, but recent studies manifested that many algal symbionts not only promote algal growth but also offer advantages in downstream processing. Because of the high expectations for microalgae in a bio‐based economy, better understanding of benefits and risks of algal–microbial associations is important for the algae industry. Reducing production cost may be through applying specific bacteria to enhance algae growth at large scale as well as through preventing the growth of a broad spectrum of algal pathogens. In this review, we highlight the latest studies of algae–microbial interactions and their underlying mechanisms, discuss advantages of large‐scale algal–bacterial cocultivation and extend such knowledge to a broad range of biotechnological applications.
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Affiliation(s)
- Jie Lian
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Rene H Wijffels
- Bioprocess Engineering Group, AlgaePARC, Wageningen University & Research, PO Box 16, 6700 AA, Wageningen, The Netherlands.,Faculty of Biosciences and Aquaculture, Nord University, N-8049, Bodø, Norway
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Detmer Sipkema
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
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Sonnenschein EC, Phippen CBW, Bentzon-Tilia M, Rasmussen SA, Nielsen KF, Gram L. Phylogenetic distribution of roseobacticides in the Roseobacter group and their effect on microalgae. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:383-393. [PMID: 29624899 DOI: 10.1111/1758-2229.12649] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 03/21/2018] [Accepted: 04/02/2018] [Indexed: 06/08/2023]
Abstract
The Roseobacter-group species Phaeobacter inhibens produces the antibacterial tropodithietic acid (TDA) and the algaecidal roseobacticides with both compound classes sharing part of the same biosynthetic pathway. The purpose of this study was to investigate the production of roseobacticides more broadly in TDA-producing roseobacters and to compare the effect of producers and non-producers on microalgae. Of 33 roseobacters analyzed, roseobacticide production was a unique feature of TDA-producing P. inhibens, P. gallaeciensis and P. piscinae strains. One TDA-producing Phaeobacter, 27-4, did not produce roseobacticides, possibly due to a transposable element. TDA-producing Ruegeria and Pseudovibrio did not produce roseobacticides. Addition of roseobacticide-containing bacterial extracts affected the growth of the microalgae Rhodomonas salina, Thalassiosira pseudonana and Emiliania huxleyi, while growth of Tetraselmis suecica was unaffected. During co-cultivation, growth of E. huxleyi was initially stimulated by the roseobacticide producer DSM 17395, while the subsequent decline in algal cell numbers during senescence was enhanced. Strain 27-4 that does not produce roseobacticides had no effect on algal growth. Both bacterial strains, DSM 17395 and 27-4, grew during co-cultivation presumably utilizing algal exudates. Furthermore, TDA-producing roseobacters have potential as probiotics in marine larviculture and it is promising that the live feed Tetraselmis was unaffected by roseobacticides-containing extracts.
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Affiliation(s)
- Eva C Sonnenschein
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Anker Engelundsvej 301, DK-2800 Kgs, Lyngby, Denmark
| | | | - Mikkel Bentzon-Tilia
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Anker Engelundsvej 301, DK-2800 Kgs, Lyngby, Denmark
| | - Silas Anselm Rasmussen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Anker Engelundsvej 301, DK-2800 Kgs, Lyngby, Denmark
| | - Kristian Fog Nielsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Anker Engelundsvej 301, DK-2800 Kgs, Lyngby, Denmark
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Anker Engelundsvej 301, DK-2800 Kgs, Lyngby, Denmark
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Biosynthesis of Tropolones in Streptomyces spp.: Interweaving Biosynthesis and Degradation of Phenylacetic Acid and Hydroxylations on the Tropone Ring. Appl Environ Microbiol 2018; 84:AEM.00349-18. [PMID: 29654178 DOI: 10.1128/aem.00349-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/05/2018] [Indexed: 01/10/2023] Open
Abstract
Tropolonoids are important natural products that contain a unique seven-membered aromatic tropolone core and exhibit remarkable biological activities. 3,7-Dihydroxytropolone (DHT) isolated from Streptomyces species is a multiply hydroxylated tropolone exhibiting antimicrobial, anticancer, and antiviral activities. In this study, we determined the DHT biosynthetic pathway by heterologous expression, gene deletion, and biotransformation. Nine trl genes and some of the aerobic phenylacetic acid degradation pathway genes (paa) located outside the trl biosynthetic gene cluster are required for the heterologous production of DHT. The trlA gene encodes a single-domain protein homologous to the C-terminal enoyl coenzyme A (enoyl-CoA) hydratase domain of PaaZ. TrlA truncates the phenylacetic acid catabolic pathway and redirects it toward the formation of heptacyclic intermediates. TrlB is a 3-deoxy-d-arabino-heptulosonic acid-7-phosphate (DAHP) synthase homolog. TrlH is an unusual bifunctional protein bearing an N-terminal prephenate dehydratase domain and a C-terminal chorismate mutase domain. TrlB and TrlH enhanced de novo biosynthesis of phenylpyruvate, thereby providing abundant precursor for the prolific production of DHT in Streptomyces spp. Six seven-membered carbocyclic compounds were identified from the trlC, trlD, trlE, and trlF deletion mutants. Four of these chemicals, including 1,4,6-cycloheptatriene-1-carboxylic acid, tropone, tropolone, and 7-hydroxytropolone, were verified as key biosynthetic intermediates. TrlF is required for the conversion of 1,4,6-cycloheptatriene-1-carboxylic acid into tropone. The monooxygenases TrlE and TrlCD catalyze the regioselective hydroxylations of tropone to produce DHT. This study reveals a natural association of anabolism of chorismate and phenylpyruvate, catabolism of phenylacetic acid, and biosynthesis of tropolones in Streptomyces spp.IMPORTANCE Tropolonoids are promising drug lead compounds because of the versatile bioactivities attributed to their highly oxidized seven-membered aromatic ring scaffolds. Our present study provides clear insight into the biosynthesis of 3,7-dihydroxytropolone (DHT) through the identification of key genes responsible for the formation and modification of the seven-membered aromatic core. We also reveal the intrinsic mechanism of elevated production of DHT and related tropolonoids in Streptomyces spp. The study on DHT biosynthesis in Streptomyces exhibits a good example of antibiotic production in which both anabolic and catabolic pathways of primary metabolism are interwoven into the biosynthesis of secondary metabolites. Furthermore, our study sets the stage for metabolic engineering of the biosynthetic pathway for natural tropolonoid products and provides alternative synthetic biology tools for engineering novel tropolonoids.
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40
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Mayali X. Editorial: Metabolic Interactions Between Bacteria and Phytoplankton. Front Microbiol 2018; 9:727. [PMID: 29692774 PMCID: PMC5902574 DOI: 10.3389/fmicb.2018.00727] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/28/2018] [Indexed: 12/02/2022] Open
Affiliation(s)
- Xavier Mayali
- Lawrence Livermore National Laboratory (DOE), Livermore, CA, United States
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41
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Wang R, Seyedsayamdost MR. Roseochelin B, an Algaecidal Natural Product Synthesized by the Roseobacter Phaeobacter inhibens in Response to Algal Sinapic Acid. Org Lett 2017; 19:5138-5141. [PMID: 28920692 DOI: 10.1021/acs.orglett.7b02424] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The secondary metabolome of the representative Roseobacter, Phaeobacter inhibens, was examined in response to algal sinapic acid. In addition to roseobacticides, sinapic acid induced the production of two new natural products, roseochelin A and B, which were characterized by NMR and X-ray crystallography. Functional assays showed that roseochelin B binds iron and is algaecidal against the algal host Emiliania huxleyi. It appears to be produced by a rarely observed combination of nonenzymatic and enzymatic transformations.
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Affiliation(s)
- Rurun Wang
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Mohammad R Seyedsayamdost
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States.,Department of Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States
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42
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Dunbar KL, Scharf DH, Litomska A, Hertweck C. Enzymatic Carbon-Sulfur Bond Formation in Natural Product Biosynthesis. Chem Rev 2017; 117:5521-5577. [PMID: 28418240 DOI: 10.1021/acs.chemrev.6b00697] [Citation(s) in RCA: 348] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Sulfur plays a critical role for the development and maintenance of life on earth, which is reflected by the wealth of primary metabolites, macromolecules, and cofactors bearing this element. Whereas a large body of knowledge has existed for sulfur trafficking in primary metabolism, the secondary metabolism involving sulfur has long been neglected. Yet, diverse sulfur functionalities have a major impact on the biological activities of natural products. Recent research at the genetic, biochemical, and chemical levels has unearthed a broad range of enzymes, sulfur shuttles, and chemical mechanisms for generating carbon-sulfur bonds. This Review will give the first systematic overview on enzymes catalyzing the formation of organosulfur natural products.
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Affiliation(s)
- Kyle L Dunbar
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI) , Beutenbergstrasse 11a, 07745 Jena, Germany
| | - Daniel H Scharf
- Life Sciences Institute, University of Michigan , 210 Washtenaw Avenue, Ann Arbor, Michigan 48109-2216, United States
| | - Agnieszka Litomska
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI) , Beutenbergstrasse 11a, 07745 Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI) , Beutenbergstrasse 11a, 07745 Jena, Germany.,Friedrich Schiller University , 07743 Jena, Germany
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43
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Segev E, Wyche TP, Kim KH, Petersen J, Ellebrandt C, Vlamakis H, Barteneva N, Paulson JN, Chai L, Clardy J, Kolter R. Dynamic metabolic exchange governs a marine algal-bacterial interaction. eLife 2016; 5. [PMID: 27855786 PMCID: PMC5148602 DOI: 10.7554/elife.17473] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 11/16/2016] [Indexed: 12/22/2022] Open
Abstract
Emiliania huxleyi is a model coccolithophore micro-alga that generates vast blooms in the ocean. Bacteria are not considered among the major factors influencing coccolithophore physiology. Here we show through a laboratory model system that the bacterium Phaeobacter inhibens, a well-studied member of the Roseobacter group, intimately interacts with E. huxleyi. While attached to the algal cell, bacteria initially promote algal growth but ultimately kill their algal host. Both algal growth enhancement and algal death are driven by the bacterially-produced phytohormone indole-3-acetic acid. Bacterial production of indole-3-acetic acid and attachment to algae are significantly increased by tryptophan, which is exuded from the algal cell. Algal death triggered by bacteria involves activation of pathways unique to oxidative stress response and programmed cell death. Our observations suggest that bacteria greatly influence the physiology and metabolism of E. huxleyi. Coccolithophore-bacteria interactions should be further studied in the environment to determine whether they impact micro-algal population dynamics on a global scale. DOI:http://dx.doi.org/10.7554/eLife.17473.001 Microscopic algae that live in the ocean release countless tons of oxygen into the atmosphere each year. Widespread algae – known as coccolithophores – surround their little plant-like body with a mineral shell made of a material similar to chalk. These microscopic algae form seasonal blooms. Over several weeks in early summer, the algae grow to enormous numbers and cover hundreds of thousands of square kilometers in the ocean. These blooms become so vast that satellites can detect them. However, suddenly the blooms collapse; the algae die and their chalky shells sink to the bottom of the ocean where they have been accumulating for millions of years. More and more evidence suggests that these tiny algae interact with bacteria in various ways. However, so far, no one had documented a direct interaction between bacteria and a member of this key group of algae. Now, in a controlled laboratory environment, Segev et al. show that marine bacteria from the Roseobacter group physically attach onto a tiny coccolithophore alga called Emiliania huxleyi. While the bacteria are attached to their algal host, they enjoy a supply of nutrients that trickles from the algal cell. Unexpectedly, Segev et al. also discovered that the algae grow better in the presence of the bacteria. It turns out that the bacteria use a molecule that they obtain from their algal hosts to produce a small hormone-like molecule that in turn enhances the growth of the algae. However, after three weeks of growing together, the bacteria produce so much of the growth-enhancing molecule – which is harmful in higher concentrations – that they actually kill their algal host. These findings suggest that the bacteria first promote the alga’s growth to boost their supply of nutrients. But as algae grow older, the bacteria harvest the algae to enjoy a last pulse of nutrients and allow their offspring to swim away and attach to younger algae. The next challenge will be to link these laboratory observations to the actual microbial interactions in the ocean. It will also be important to explore whether other algae and bacteria interact in similar ways and if bacteria contribute to the sudden collapse of algal blooms by killing the algae. DOI:http://dx.doi.org/10.7554/eLife.17473.002
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Affiliation(s)
- Einat Segev
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
| | - Thomas P Wyche
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Ki Hyun Kim
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Jörn Petersen
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany
| | - Claire Ellebrandt
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany
| | - Hera Vlamakis
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
| | - Natasha Barteneva
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, United States
| | - Joseph N Paulson
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, United States
| | - Liraz Chai
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
| | - Jon Clardy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Roberto Kolter
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
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