1
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Ma ZX, Feng CX, Song YZ, Sun J, Shao Y, Song SZ, Wan B, Zhang C, Fan H, Bao K, Yang S. Engineering photo-methylotrophic Methylobacterium for enhanced 3-hydroxypropionic acid production during non-growth stage fermentation. BIORESOURCE TECHNOLOGY 2024; 393:130104. [PMID: 38008225 DOI: 10.1016/j.biortech.2023.130104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/23/2023] [Accepted: 11/23/2023] [Indexed: 11/28/2023]
Abstract
This study explored the potential of methanol as a sustainable feedstock for biomanufacturing, focusing on Methylobacterium extorquens, a well-established representative of methylotrophic cell factories. Despite this bacterium's long history, its untapped photosynthetic capabilities for production enhancement have remained unreported. Using genome-scale flux balance analysis, it was hypothesized that introducing photon fluxes could boost the yield of 3-hydroxypropionic acid (3-HP), an energy- and reducing equivalent-consuming chemicals. To realize this, M. extorquens was genetically modified by eliminating the negative regulator of photosynthesis, leading to improved ATP levels and metabolic activity in non-growth cells during a two-stage fermentation process. This modification resulted in a remarkable 3.0-fold increase in 3-HP titer and a 2.1-fold increase in its yield during stage (II). Transcriptomics revealed that enhanced light-driven methanol oxidation, NADH transhydrogenation, ATP generation, and fatty acid degradation were key factors. This development of photo-methylotrophy as a platform technology introduced novel opportunities for future production enhancements.
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Affiliation(s)
- Zeng-Xin Ma
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China
| | - Chen-Xi Feng
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China
| | - Ya-Zhen Song
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China
| | - Jing Sun
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China
| | - Yi Shao
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China
| | - Shu-Zhen Song
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China
| | - Bin Wan
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China
| | - Cong Zhang
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China
| | - Huan Fan
- Tianjin Key Laboratory of Animal Molecular Breeding and Biotechnology, Tianjin Engineering Research Center of Animal Healthy Farming, Institute of Animal Science and Veterinary, Tianjin Academy of Agricultural Sciences, Tianjin 300381, People's Republic of China
| | - Kai Bao
- School of Life Sciences, Hubei University, Wuhan 430062, Hubei, People's Republic of China
| | - Song Yang
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, and Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin 300072, People's Republic of China.
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2
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Tinguely C, Paulméry M, Terrettaz C, Gonzalez D. Diurnal cycles drive rhythmic physiology and promote survival in facultative phototrophic bacteria. ISME COMMUNICATIONS 2023; 3:125. [PMID: 38001234 PMCID: PMC10674011 DOI: 10.1038/s43705-023-00334-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 11/02/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023]
Abstract
Bacteria have evolved many strategies to spare energy when nutrients become scarce. One widespread such strategy is facultative phototrophy, which helps heterotrophs supplement their energy supply using light. Our knowledge of the impact that such behaviors have on bacterial fitness and physiology is, however, still limited. Here, we study how a representative of the genus Porphyrobacter, in which aerobic anoxygenic phototrophy is ancestral, responds to different light regimes under nutrient limitation. We show that bacterial survival in stationary phase relies on functional reaction centers and varies depending on the light regime. Under dark-light alternance, our bacterial model presents a diphasic life history dependent on phototrophy: during dark phases, the cells inhibit DNA replication and part of the population lyses and releases nutrients, while subsequent light phases allow for the recovery and renewed growth of the surviving cells. We correlate these cyclic variations with a pervasive pattern of rhythmic transcription which reflects global changes in diurnal metabolic activity. Finally, we demonstrate that, compared to either a phototrophy mutant or a bacteriochlorophyll a overproducer, the wild type strain is better adapted to natural environments, where regular dark-light cycles are interspersed with additional accidental dark episodes. Overall, our results highlight the importance of light-induced biological rhythms in a new model of aerobic anoxygenic phototroph representative of an ecologically important group of environmental bacteria.
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Affiliation(s)
- Camille Tinguely
- Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Mélanie Paulméry
- Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Céline Terrettaz
- Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Diego Gonzalez
- Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
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3
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Li L, Huang D, Hu Y, Rudling NM, Canniffe DP, Wang F, Wang Y. Globally distributed Myxococcota with photosynthesis gene clusters illuminate the origin and evolution of a potentially chimeric lifestyle. Nat Commun 2023; 14:6450. [PMID: 37833297 PMCID: PMC10576062 DOI: 10.1038/s41467-023-42193-7] [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: 02/24/2023] [Accepted: 10/02/2023] [Indexed: 10/15/2023] Open
Abstract
Photosynthesis is a fundamental biogeochemical process, thought to be restricted to a few bacterial and eukaryotic phyla. However, understanding the origin and evolution of phototrophic organisms can be impeded and biased by the difficulties of cultivation. Here, we analyzed metagenomic datasets and found potential photosynthetic abilities encoded in the genomes of uncultivated bacteria within the phylum Myxococcota. A putative photosynthesis gene cluster encoding a type-II reaction center appears in at least six Myxococcota families from three classes, suggesting vertical inheritance of these genes from an early common ancestor, with multiple independent losses in other lineages. Analysis of metatranscriptomic datasets indicate that the putative myxococcotal photosynthesis genes are actively expressed in various natural environments. Furthermore, heterologous expression of myxococcotal pigment biosynthesis genes in a purple bacterium supports that the genes can drive photosynthetic processes. Given that predatory abilities are thought to be widespread across Myxococcota, our results suggest the intriguing possibility of a chimeric lifestyle (combining predatory and photosynthetic abilities) in members of this phylum.
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Affiliation(s)
- Liuyang Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Danyue Huang
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Yaoxun Hu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Nicola M Rudling
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Daniel P Canniffe
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Fengping Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200030, China.
| | - Yinzhao Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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4
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Sun KM, Wang J, Ju Q, Zhao Y, Kong X, Yuan C, Tian Y. The mitigating effects of diatom-bacteria biofilm on coastal harmful algal blooms: A lab-based study concerning species-specific competition and biofilm formation. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 335:117544. [PMID: 36842356 DOI: 10.1016/j.jenvman.2023.117544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/15/2022] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Harmful algal blooms (HABs) in coastal areas severely affected the health of ecosystem and human beings. The HABs control by biological methods, especially for biofilms, has been research hotspots in freshwater ecosystem. However, the biofilm-relating control of HABs in marine environment was very limited. In the present study, we found the population growth of two harmful algal species, Prorocentrum obtusidens Schiller (formerly P. donghaiense Lu) and Heterosigma akashiwo, were inhibited by a diatom-bacteria biofilm. The highest inhibitory rate was 79.6 ± 2.1% for P. obtusidens when co-cultured with biofilm suspension, and was 88.6 ± 5.8% for H. akashiwo when co-cultured with the biofilm filtrate without nutrient replenishment. When nitrate and phosphate were added, the inhibition rate for P. obtusidens was 72.3 ± 2.0%, but the population inhibition was not found in H. akashiwo. It suggested that P. obtusidens was mainly inhibited via interference competition, while the inhibition of H. akashiwo was resulted from exploitation competition. We further investigated the role of fatty acids for the interference competition in P. obtusidens, and found that fatty acids at their environmental-relevance concentrations can inhibit the photosynthetic capacity of P. obtusidens, but cannot inhibit the population growth. The community of biofilm shifted, and was finally dominated by the photoheterotrophic bacterium Dinoroseobacter shibae, and the diatom Fistulifera sp. with relative abundance of higher than 90%. Our study indicated that the diatom-bacteria biofilm was likely the candidate for the HABs control in marine environment. D. shibae and Fistulifera sp. were probably the effective species in the biofilm.
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Affiliation(s)
- Kai-Ming Sun
- Institute of Oceanographic Instrumentation, Qilu University of Technology (Shandong Academy of Sciences), Qingdao, 266100, Shandong, China; SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, Shandong, China
| | - Jingru Wang
- Institute of Oceanographic Instrumentation, Qilu University of Technology (Shandong Academy of Sciences), Qingdao, 266100, Shandong, China
| | - Qing Ju
- Shandong Provincial Qingdao Eco-environment Monitoring Center, Qingdao, 266061, Shandong, China
| | - Yan Zhao
- College of Marine Life, Ocean University of China, Qingdao, 266003, Shandong, China
| | - Xiangfeng Kong
- Institute of Oceanographic Instrumentation, Qilu University of Technology (Shandong Academy of Sciences), Qingdao, 266100, Shandong, China
| | - Chao Yuan
- SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, Shandong, China.
| | - Yulu Tian
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China.
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Suyama T, Kanno N, Matsukura S, Chihara K, Noda N, Hanada S. Transcriptome and Deletion Mutant Analyses Revealed that an RpoH Family Sigma Factor Is Essential for Photosystem Production in Roseateles depolymerans under Carbon Starvation. Microbes Environ 2023; 38. [PMID: 36878600 PMCID: PMC10037100 DOI: 10.1264/jsme2.me22072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023] Open
Abstract
Roseateles depolymerans is an obligately aerobic bacterium that produces a photosynthetic apparatus only under the scarcity of carbon substrates. We herein examined changes in the transcriptomes of R. depolymerans cells to clarify the expression of photosynthesis genes and their upstream regulatory factors under carbon starvation. Transcriptomes 0, 1, and 6 h after the depletion of a carbon substrate indicated that transcripts showing the greatest variations (a 500-fold increase [6 h/0 h]) were light-harvesting proteins (PufA and PufB). Moreover, loci with more than 50-fold increases (6 h/0 h) were fully related to the photosynthetic gene cluster. Among 13 sigma factor genes, the transcripts of a sigma 70 family sigma factor related to RpoH (SP70) increased along photosynthesis genes under starvation; therefore, a knockout experiment of SP70 was performed. ΔSP70 mutants were found to lack photosynthetic pigments (carotenoids and bacteriochlo-rophyll a) regardless of carbon starvation. We also examined the effects of heat stress on ΔSP70 mutants, and found that SP70 was also related to heat stress tolerance, similar to other RpoH sigma factors (while heat stress did not trigger photosystem production). The deficient accumulation of photosynthetic pigments and the heat stress tolerance of ΔSP70 mutants were both complemented by the introduction of an intact SP70 gene. Furthermore, the transcription of photosynthetic gene operons (puf, puh, and bch) was markedly reduced in the ΔSP70 mutant. The RpoH homologue SP70 was concluded to be a sigma factor that is essential for the transcription of photosynthetic gene operons in R. depolymerans.
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Affiliation(s)
- Tetsushi Suyama
- Bio-Analytical Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Nanako Kanno
- Photosynthetic Microbial Consortia Laboratory, Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University
| | - Satoko Matsukura
- Bio-Analytical Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Kotaro Chihara
- Bio-Analytical Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
- Department of Life Science and Medical Bioscience, Waseda University
| | - Naohiro Noda
- Bio-Analytical Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
- Department of Life Science and Medical Bioscience, Waseda University
| | - Satoshi Hanada
- Photosynthetic Microbial Consortia Laboratory, Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University
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6
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Kopejtka K, Tomasch J, Zeng Y, Selyanin V, Dachev M, Piwosz K, Tichý M, Bína D, Gardian Z, Bunk B, Brinkmann H, Geffers R, Sommaruga R, Koblížek M. Simultaneous Presence of Bacteriochlorophyll and Xanthorhodopsin Genes in a Freshwater Bacterium. mSystems 2020; 5:e01044-20. [PMID: 33361324 PMCID: PMC7762795 DOI: 10.1128/msystems.01044-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 11/30/2020] [Indexed: 01/01/2023] Open
Abstract
Photoheterotrophic bacteria represent an important part of aquatic microbial communities. There exist two fundamentally different light-harvesting systems: bacteriochlorophyll-containing reaction centers or rhodopsins. Here, we report a photoheterotrophic Sphingomonas strain isolated from an oligotrophic lake, which contains complete sets of genes for both rhodopsin-based and bacteriochlorophyll-based phototrophy. Interestingly, the identified genes were not expressed when cultured in liquid organic media. Using reverse transcription quantitative PCR (RT-qPCR), RNA sequencing, and bacteriochlorophyll a quantification, we document that bacteriochlorophyll synthesis was repressed by high concentrations of glucose or galactose in the medium. Coactivation of photosynthesis genes together with genes for TonB-dependent transporters suggests the utilization of light energy for nutrient import. The photosynthetic units were formed by ring-shaped light-harvesting complex 1 and reaction centers with bacteriochlorophyll a and spirilloxanthin as the main light-harvesting pigments. The identified rhodopsin gene belonged to the xanthorhodopsin family, but it lacks salinixanthin antenna. In contrast to bacteriochlorophyll, the expression of xanthorhodopsin remained minimal under all experimental conditions tested. Since the gene was found in the same operon as a histidine kinase, we propose that it might serve as a light sensor. Our results document that photoheterotrophic Sphingomonas bacteria use the energy of light under carbon-limited conditions, while under carbon-replete conditions, they cover all their metabolic needs through oxidative phosphorylation.IMPORTANCE Phototrophic organisms are key components of many natural environments. There exist two main phototrophic groups: species that collect light energy using various kinds of (bacterio)chlorophylls and species that utilize rhodopsins. Here, we present a freshwater bacterium Sphingomonas sp. strain AAP5 which contains genes for both light-harvesting systems. We show that bacteriochlorophyll-based reaction centers are repressed by light and/or glucose. On the other hand, the rhodopsin gene was not expressed significantly under any of the experimental conditions. This may indicate that rhodopsin in Sphingomonas may have other functions not linked to bioenergetics.
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Affiliation(s)
- Karel Kopejtka
- Center Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czechia
| | - Jürgen Tomasch
- Research Group Microbial Communication, Technical University of Braunschweig, Braunschweig, Germany
| | - Yonghui Zeng
- Center Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czechia
- Department of Environmental Science, Aarhus University, Aarhus, Denmark
| | - Vadim Selyanin
- Center Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czechia
| | - Marko Dachev
- Center Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czechia
| | - Kasia Piwosz
- Center Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czechia
| | - Martin Tichý
- Center Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czechia
| | - David Bína
- Institute of Plant Molecular Biology, Biology Center of the Czech Academy of Sciences, České Budějovice, Czechia
- Institute of Parasitology, Biology Center of the Czech Academy of Sciences, České Budějovice, Czechia
- Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Zdenko Gardian
- Institute of Plant Molecular Biology, Biology Center of the Czech Academy of Sciences, České Budějovice, Czechia
- Institute of Parasitology, Biology Center of the Czech Academy of Sciences, České Budějovice, Czechia
- Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Henner Brinkmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Robert Geffers
- Research Group Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ruben Sommaruga
- Laboratory of Aquatic Photobiology and Plankton Ecology, Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Michal Koblížek
- Center Algatech, Institute of Microbiology of the Czech Academy of Science, Třeboň, Czechia
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7
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Giebel HA, Wolterink M, Brinkhoff T, Simon M. Complementary energy acquisition via aerobic anoxygenic photosynthesis and carbon monoxide oxidation by Planktomarina temperata of the Roseobacter group. FEMS Microbiol Ecol 2020; 95:5437672. [PMID: 31055603 DOI: 10.1093/femsec/fiz050] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/05/2019] [Indexed: 02/06/2023] Open
Abstract
In marine pelagic ecosystems energy is often the limiting factor for growth of heterotrophic bacteria. Aerobic anoxygenic photosynthesis (AAP) and oxidation of carbon monoxide (CO) are modes to acquire complementary energy, but their significance in abundant and characteristic pelagic marine bacteria has not been well studied. In long-term batch culture experiments we found that Planktomarina temperata RCA23, representing the largest and most prominent subcluster of the Roseobacter group, maintains 2-3-fold higher cell numbers in the stationary and declining phase when grown in a light-dark cycle relative to dark conditions. Light enables P. temperata to continue to replicate its DNA during the stationary phase relative to a dark control such that when reinoculated into fresh medium growth resumed two days earlier than in control cultures. In cultures grown in the dark and supplemented with CO, cell numbers in the stationary phase remained significantly higher than in an unsupplemented control. Furthermore, repeated spiking with CO until day 372 resulted in significant CO consumption relative to an unsupplemented control. P. temperata represents a prominent marine pelagic bacterium for which AAP and CO consumption, to acquire complementary energy, have been documented.
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Affiliation(s)
- Helge-Ansgar Giebel
- Institute of Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Mathias Wolterink
- Institute of Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Thorsten Brinkhoff
- Institute of Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Meinhard Simon
- Institute of Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
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8
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Robador A, Amend JP, Finkel SE. Nanocalorimetry Reveals the Growth Dynamics of Escherichia coli Cells Undergoing Adaptive Evolution during Long-Term Stationary Phase. Appl Environ Microbiol 2019; 85:e00968-19. [PMID: 31152016 PMCID: PMC6643242 DOI: 10.1128/aem.00968-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 05/24/2019] [Indexed: 11/20/2022] Open
Abstract
Bacterial populations in long-term stationary-phase (LTSP) laboratory cultures can provide insights into physiological and genetic adaptations to low-energy conditions and population dynamics in natural environments. While overall population density remains stable, these communities are very dynamic and are characterized by the rapid emergence and succession of distinct mutants expressing the growth advantage in stationary phase (GASP) phenotype, which can reflect an increased capacity to withstand energy limitations and environmental stress. Here, we characterize the metabolic heat signatures and growth dynamics of GASP mutants within an evolving population using isothermal calorimetry. We aged Escherichia coli in anaerobic batch cultures over 20 days inside an isothermal nanocalorimeter and observed distinct heat events related to the emergence of three mutant populations expressing the GASP phenotype after 1.5, 3, and 7 days. Given the heat produced by each population, the maximum number of GASP mutant cells was calculated, revealing abundances of ∼2.5 × 107, ∼7.5 × 106, and ∼9.9 × 106 cells in the populations, respectively. These data indicate that mutants capable of expressing the GASP phenotype can be acquired during the exponential growth phase and subsequently expressed in LTSP culture.IMPORTANCE The present study is innovative in that we have identified previously unknown growth dynamics related to the temporal expression of the growth advantage in stationary phase (GASP) phenotype that allow mutants in long-term stationary-phase cultures to capitalize on the decrease of energy over prolonged incubation periods. By remaining in an active, but growth-limited, metabolic state similar to that observed in GASP cells grown in vitro, natural microbial communities might be able to prevail over much longer time scales. We believe this report to be a remarkable methodological and conceptual breakthrough in the study of the long-term survival and evolution of bacteria.
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Affiliation(s)
- Alberto Robador
- Center for Dark Energy Biosphere Investigations (C-DEBI), University of Southern California, Los Angeles, California, USA
- Marine and Environmental Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Jan P Amend
- Center for Dark Energy Biosphere Investigations (C-DEBI), University of Southern California, Los Angeles, California, USA
- Marine and Environmental Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
| | - Steven E Finkel
- Center for Dark Energy Biosphere Investigations (C-DEBI), University of Southern California, Los Angeles, California, USA
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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9
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Vedalankar P, Tripathy BC. Evolution of light-independent protochlorophyllide oxidoreductase. PROTOPLASMA 2019; 256:293-312. [PMID: 30291443 DOI: 10.1007/s00709-018-1317-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 09/27/2018] [Indexed: 06/08/2023]
Abstract
The nonhomologous enzymes, the light-independent protochlorophyllide reductase (DPOR) and the light-dependent protochlorophyllide oxidoreductase (LPOR), catalyze the reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide) in the penultimate step of biosynthesis of chlorophyll (Chl) required for photosynthetic light absorption and energy conversion. The two enzymes differ with respect to the requirement of light for catalysis and oxygen sensitivity. DPOR and LPOR initially evolved in the ancestral prokaryotic genome perhaps at different times. DPOR originated in the anoxygenic environment of the Earth from nitrogenase-like enzyme of methanogenic archaea. Due to the transition from anoxygenic to oxygenic photosynthesis in the prokaryote, the DPOR was mostly inactivated in the daytime by photosynthetic O2 leading to the evolution of oxygen-insensitive LPOR that could function in the light. The primary endosymbiotic event transferred the DPOR and LPOR genes to the eukaryotic phototroph; the DPOR remained in the genome of the ancestor that turned into the plastid, whereas LPOR was transferred to the host nuclear genome. From an evolutionary point of view, several compelling theories that explain the disappearance of DPOR from several species cutting across different phyla are as follows: (i) pressure of the oxygenic environment; (ii) change in the light conditions and temperature; and (iii) lineage-specific gene losses, RNA editing, and nonsynonymous substitution. Certain primary amino acid sequence and the physiochemical properties of the ChlL subunit of DPOR have similarity with that of LPOR suggesting a convergence of these two enzymes in certain evolutionary event. The newly obtained sequence data from different phototrophs will further enhance the width of the phylogenetic information on DPOR.
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Affiliation(s)
| | - Baishnab C Tripathy
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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10
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Tang K, Jia L, Yuan B, Yang S, Li H, Meng J, Zeng Y, Feng F. Aerobic Anoxygenic Phototrophic Bacteria Promote the Development of Biological Soil Crusts. Front Microbiol 2018; 9:2715. [PMID: 30483234 PMCID: PMC6243035 DOI: 10.3389/fmicb.2018.02715] [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: 08/13/2018] [Accepted: 10/23/2018] [Indexed: 12/14/2022] Open
Abstract
Chlorophyll-containing oxygenic photoautotrophs have been well known to play a fundamental role in the development of biological soil crusts (BSCs) by harvesting solar radiations and providing fixed carbon to the BSCs ecosystems. Although the same functions can be theoretically fulfilled by the widespread bacteriochlorophyll-harboring aerobic anoxygenic phototrophic bacteria (AAnPB), whether AAnPB play a role in the formation of BSCs and how important they are to this process remain largely unknown. To address these questions, we set up a microcosm system with surface sands of the Hopq desert in northern China and observed the significant effects of near-infrared illumination on the development of BSCs. Compared to near-infrared or red light alone, the combined use of near-infrared and red lights for illumination greatly increased the thickness of BSCs, their organic matter contents and the microalgae abundance by 24.0, 103.7, and 1447.6%, respectively. These changes were attributed to the increasing abundance of AAnPB that can absorb near-infrared radiations. Our data suggest that AAnPB is a long-overlooked driver in promoting the development of BSCs in drylands.
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Affiliation(s)
- Kai Tang
- Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Huhhot, China
| | - Lijuan Jia
- Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Huhhot, China
| | - Bo Yuan
- Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Huhhot, China.,College of Life Science, Inner Mongolia Normal University, Huhhot, China
| | - Shanshan Yang
- Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Huhhot, China
| | - Heng Li
- Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Huhhot, China
| | - Jianyu Meng
- Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Huhhot, China
| | - Yonghui Zeng
- Aarhus Institute of Advanced Studies, Aarhus, Denmark.,Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Fuying Feng
- Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Huhhot, China
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11
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Kirchhoff C, Ebert M, Jahn D, Cypionka H. Chemiosmotic Energy Conservation in Dinoroseobacter shibae: Proton Translocation Driven by Aerobic Respiration, Denitrification, and Photosynthetic Light Reaction. Front Microbiol 2018; 9:903. [PMID: 29867814 PMCID: PMC5954134 DOI: 10.3389/fmicb.2018.00903] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 04/18/2018] [Indexed: 11/13/2022] Open
Abstract
Dinoroseobacter shibae is an aerobic anoxygenic phototroph and able to utilize light energy to support its aerobic energy metabolism. Since the cells can also grow anaerobically with nitrate and nitrite as terminal electron acceptor, we were interested in how the cells profit from photosynthesis during denitrification and what the steps of chemiosmotic energy conservation are. Therefore, we conducted proton translocation experiments and compared O2-, NO3-, and NO2- respiration during different light regimes and in the dark. We used wild type cells and transposon mutants with knocked-out nitrate- and nitrite- reductase genes (napA and nirS), as well as a mutant (ppsR) impaired in bacteriochlorophyll a synthesis. Light had a positive impact on proton translocation, independent of the type of terminal electron acceptor present. In the absence of an electron acceptor, however, light did not stimulate proton translocation. The light-driven add-on to proton translocation was about 1.4 H+/e- for O2 respiration and about 1.1 H+/e- for NO3- and NO2-. We could see that the chemiosmotic energy conservation during aerobic respiration involved proton translocation, mediated by the NADH dehydrogenase, the cytochrome bc1 complex, and the cytochrome c oxidase. During denitrification the last proton translocation step of the electron transport was missing, resulting in a lower H+/e- ratio during anoxia. Furthermore, we studied the type of light-harvesting and found that the cells were able to channel light from the green–blue spectrum most efficiently, while red light has only minor impact. This fits well with the depth profiles for D. shibae abundance in the ocean and the penetration depth of light with different wavelengths into the water column.
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Affiliation(s)
- Christian Kirchhoff
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Matthias Ebert
- Institute of Microbiology, Braunschweig University of Technology, Braunschweig, Germany
| | - Dieter Jahn
- Institute of Microbiology, Braunschweig University of Technology, Braunschweig, Germany
| | - Heribert Cypionka
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
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12
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Sebastián M, Auguet JC, Restrepo-Ortiz CX, Sala MM, Marrasé C, Gasol JM. Deep ocean prokaryotic communities are remarkably malleable when facing long-term starvation. Environ Microbiol 2017; 20:713-723. [PMID: 29159926 DOI: 10.1111/1462-2920.14002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 11/17/2017] [Indexed: 11/28/2022]
Abstract
The bathypelagic ocean is one of the largest ecosystems on Earth and sustains half of the ocean's microbial activity. This microbial activity strongly relies on surface-derived particles, but there is growing evidence that the carbon released through solubilization of these particles may not be sufficient to meet the energy demands of deep ocean prokaryotes. To explore how bathypelagic prokaryotes respond to the absence of external inputs of carbon, we followed the long-term (1 year) dynamics of an enclosed community. Despite the lack of external energy supply, we observed a continuous succession of active prokaryotic phylotypes, which was driven by recruitment of taxa from the seed bank (i.e., initially rare operational taxonomic units [OTUs]). A single OTU belonging to Marine Group I of Thaumarchaeota, which was originally rare, dominated the microbial community for ∼ 4 months and played a fundamental role in this succession likely by introducing new organic carbon through chemolithoautotrophy. This carbon presumably produced a priming effect, because after the decline of Thaumarchaeota, the diversity and metabolic potential of the community increased back to the levels present at the start of the experiment. Our study demonstrates the profound versatility of deep microbial communities when facing organic carbon deprivation.
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Affiliation(s)
- Marta Sebastián
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar CSIC, Passeig Marítim de la Barceloneta, 37-49, E08003 Barcelona, Catalunya, Spain.,Instituto de Oceanografía y Cambio Global, Universidad de Las Palmas de Gran Canaria, Parque Científico Tecnológico Marino de Taliarte, s/n 35214, Telde, Spain
| | - Jean-Christophe Auguet
- Marine Biodiversity, Exploitation and Conservation (MARBEC), UMR CNRS 9190, Université de Montpellier, CC093, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
| | - Claudia Ximena Restrepo-Ortiz
- Marine Biodiversity, Exploitation and Conservation (MARBEC), UMR CNRS 9190, Université de Montpellier, CC093, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
| | - María Montserrat Sala
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar CSIC, Passeig Marítim de la Barceloneta, 37-49, E08003 Barcelona, Catalunya, Spain
| | - Celia Marrasé
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar CSIC, Passeig Marítim de la Barceloneta, 37-49, E08003 Barcelona, Catalunya, Spain
| | - Josep M Gasol
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar CSIC, Passeig Marítim de la Barceloneta, 37-49, E08003 Barcelona, Catalunya, Spain
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13
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Piwosz K, Kaftan D, Dean J, Šetlík J, Koblížek M. Nonlinear effect of irradiance on photoheterotrophic activity and growth of the aerobic anoxygenic phototrophic bacteriumDinoroseobacter shibae. Environ Microbiol 2017; 20:724-733. [DOI: 10.1111/1462-2920.14003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 11/10/2017] [Accepted: 11/17/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Kasia Piwosz
- Center Algatech; Institute of Microbiology CAS; Třeboň 37981 Czech Republic
| | - David Kaftan
- Center Algatech; Institute of Microbiology CAS; Třeboň 37981 Czech Republic
| | - Jason Dean
- Center Algatech; Institute of Microbiology CAS; Třeboň 37981 Czech Republic
| | - Jiří Šetlík
- Center Algatech; Institute of Microbiology CAS; Třeboň 37981 Czech Republic
| | - Michal Koblížek
- Center Algatech; Institute of Microbiology CAS; Třeboň 37981 Czech Republic
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14
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Kirchhoff C, Cypionka H. Propidium ion enters viable cells with high membrane potential during live-dead staining. J Microbiol Methods 2017; 142:79-82. [DOI: 10.1016/j.mimet.2017.09.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 09/05/2017] [Accepted: 09/14/2017] [Indexed: 11/28/2022]
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15
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Wienhausen G, Noriega-Ortega BE, Niggemann J, Dittmar T, Simon M. The Exometabolome of Two Model Strains of the Roseobacter Group: A Marketplace of Microbial Metabolites. Front Microbiol 2017; 8:1985. [PMID: 29075248 PMCID: PMC5643483 DOI: 10.3389/fmicb.2017.01985] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/27/2017] [Indexed: 12/04/2022] Open
Abstract
Recent studies applying Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) showed that the exometabolome of marine bacteria is composed of a surprisingly high molecular diversity. To shed more light on how this diversity is generated we examined the exometabolome of two model strains of the Roseobacter group, Phaeobacter inhibens and Dinoroseobacter shibae, grown on glutamate, glucose, acetate or succinate by FT-ICR-MS. We detected 2,767 and 3,354 molecular formulas in the exometabolome of each strain and 67 and 84 matched genome-predicted metabolites of P. inhibens and D. shibae, respectively. The annotated compounds include late precursors of biosynthetic pathways of vitamins B1, B2, B5, B6, B7, B12, amino acids, quorum sensing-related compounds, indole acetic acid and methyl-(indole-3-yl) acetic acid. Several formulas were also found in phytoplankton blooms. To shed more light on the effects of some of the precursors we supplemented two B1 prototrophic diatoms with the detected precursor of vitamin B1 HET (4-methyl-5-(β-hydroxyethyl)thiazole) and HMP (4-amino-5-hydroxymethyl-2-methylpyrimidine) and found that their growth was stimulated. Our findings indicate that both strains and other bacteria excreting a similar wealth of metabolites may function as important helpers to auxotrophic and prototrophic marine microbes by supplying growth factors and biosynthetic precursors.
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Affiliation(s)
- Gerrit Wienhausen
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Beatriz E Noriega-Ortega
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Jutta Niggemann
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Thorsten Dittmar
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Meinhard Simon
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
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16
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Bill N, Tomasch J, Riemer A, Müller K, Kleist S, Schmidt-Hohagen K, Wagner-Döbler I, Schomburg D. Fixation of CO 2 using the ethylmalonyl-CoA pathway in the photoheterotrophic marine bacterium Dinoroseobacter shibae. Environ Microbiol 2017; 19:2645-2660. [PMID: 28371065 DOI: 10.1111/1462-2920.13746] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 03/25/2017] [Accepted: 03/25/2017] [Indexed: 01/26/2023]
Abstract
The ability of aerobic anoxygenic photoheterotrophs (AAPs) to gain additional energy from sunlight represents a competitive advantage, especially in conditions where light has easy access or under environmental conditions may change quickly, such as those in the world´s oceans. However, the knowledge about the metabolic consequences of aerobic anoxygenic photosynthesis is very limited. Combining transcriptome and metabolome analyses, isotopic labelling techniques, measurements of growth, oxygen uptake rates, flow cytometry, and a number of other biochemical analytical techniques we obtained a comprehensive overview on the complex adaption of the marine bacterium Dinoroseobacter shibae DFL12T during transition from heterotrophy to photoheterotrophy (growth on succinate). Growth in light was characterized by reduced respiration, a decreased metabolic flux through the tricarboxylic acid (TCA) cycle and the assimilation of CO2 via an enhanced flux through the ethylmalonyl-CoA (EMC) pathway, which was shown to be connected to the serine metabolism. Adaptation to photoheterotrophy is mainly characterized by metabolic reactions caused by a surplus of reducing potential and might depend on genes located in one operon, encoding branching point enzymes of the EMC pathway, serine metabolism and the TCA cycle.
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Affiliation(s)
- Nelli Bill
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Rebenring 56, Braunschweig, D-38106, Germany
| | - Jürgen Tomasch
- Department of Microbial Communication, Helmholtz-Centre for Infection Research (HZI), Inhoffenstrasse 7, Braunschweig, D-38124, Germany
| | - Alexander Riemer
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Rebenring 56, Braunschweig, D-38106, Germany
| | - Katrin Müller
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Rebenring 56, Braunschweig, D-38106, Germany
| | - Sarah Kleist
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Rebenring 56, Braunschweig, D-38106, Germany
| | - Kerstin Schmidt-Hohagen
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Rebenring 56, Braunschweig, D-38106, Germany
| | - Irene Wagner-Döbler
- Department of Microbial Communication, Helmholtz-Centre for Infection Research (HZI), Inhoffenstrasse 7, Braunschweig, D-38124, Germany
| | - Dietmar Schomburg
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Rebenring 56, Braunschweig, D-38106, Germany
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17
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Kirchhoff C, Cypionka H. Boosted Membrane Potential as Bioenergetic Response to Anoxia in Dinoroseobacter shibae. Front Microbiol 2017; 8:695. [PMID: 28473821 PMCID: PMC5397407 DOI: 10.3389/fmicb.2017.00695] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 04/04/2017] [Indexed: 11/29/2022] Open
Abstract
Dinoroseobacter shibae DFL 12T is a metabolically versatile member of the world-wide abundant Roseobacter clade. As an epibiont of dinoflagellates D. shibae is subjected to rigorous changes in oxygen availability. It has been shown that it loses up to 90% of its intracellular ATP when exposed to anoxic conditions. Yet, D. shibae regenerates its ATP level quickly when oxygen becomes available again. In the present study we focused on the bioenergetic aspects of the quick recovery and hypothesized that the proton-motive force decreases during anoxia and gets restored upon re-aeration. Therefore, we analyzed ΔpH and the membrane potential (ΔΨ) during the oxic-anoxic transitions. To visualize changes of ΔΨ we used fluorescence microscopy and the carbocyanine dyes DiOC2 (3; 3,3′-Diethyloxacarbocyanine Iodide) and JC-10. In control experiments the ΔΨ-decreasing effects of the chemiosmotic inhibitors CCCP (carbonyl cyanide m-chlorophenyl hydrazone), TCS (3,3′,4′,5-tetrachlorosalicylanilide) and gramicidin were tested on D. shibae and Gram-negative and -positive control bacteria (Escherichia coli and Micrococcus luteus). We found that ΔpH is not affected by short-term anoxia and does not contribute to the quick ATP regeneration in D. shibae. By contrast, ΔΨ was increased during anoxia, which was astonishing since none of the control organisms behaved that way. Our study shows physiological and bioenergetical aspects comparing to previous studies on transcriptomic responses to the transition from aerobic to nitrate respiration in D. shibae. For the lifestyle as an epibiont of a dinoflagellate, the ability to stand phases of temporary oxygen depletion is beneficial. With a boosted ΔΨ, the cells are able to give their ATP regeneration a flying start, once oxygen is available again.
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Affiliation(s)
- Christian Kirchhoff
- Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky University of OldenburgOldenburg, Germany
| | - Heribert Cypionka
- Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky University of OldenburgOldenburg, Germany
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18
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Koblížek M. Ecology of aerobic anoxygenic phototrophs in aquatic environments. FEMS Microbiol Rev 2015; 39:854-70. [DOI: 10.1093/femsre/fuv032] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2015] [Indexed: 11/13/2022] Open
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19
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Soora M, Tomasch J, Wang H, Michael V, Petersen J, Engelen B, Wagner-Döbler I, Cypionka H. Oxidative stress and starvation in Dinoroseobacter shibae: the role of extrachromosomal elements. Front Microbiol 2015; 6:233. [PMID: 25859246 PMCID: PMC4373377 DOI: 10.3389/fmicb.2015.00233] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/10/2015] [Indexed: 12/31/2022] Open
Abstract
Aerobic anoxygenic phototrophic bacteria (AAP) are abundant in the photic zone of the marine environment. Dinoroseobacter shibae, a representative of the Roseobacter group, converts light into additional energy that enhances its survival especially under starvation. However, light exposure results in the production of cytotoxic reactive oxygen species in AAPs. Here we investigated the response of D. shibae to starvation and oxidative stress, focusing on the role of extrachromosomal elements (ECRs). D. shibae possessing five ECRs (three plasmids and two chromids) was starved for 4 weeks either in the dark or under light/dark cycles and the survival was monitored. Transcriptomics showed that on the chromosome genes with a role in oxidative stress response and photosynthesis were differentially expressed during the light period. Most extrachromosomal genes in contrast showed a general loss of transcriptional activity, especially in dark-starved cells. The observed decrease of gene expression was not due to plasmid loss, as all five ECRs were maintained in the cells. Interestingly, the genes on the 72-kb chromid were the least downregulated, and one region with genes of the oxygen stress response and a light-dependent protochlorophyllide reductase of cyanobacterial origin was strongly activated under the light/dark cycle. A Δ72-kb curing mutant lost the ability to survive under starvation in a light/dark cycle demonstrating the essential role of this chromid for adaptation to starvation and oxidative stress. Our data moreover suggest that the other four ECRs of D. shibae have no vital function under the investigated conditions and therefore were transcriptionally silenced.
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Affiliation(s)
- Maya Soora
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University of Oldenburg Oldenburg, Germany
| | - Jürgen Tomasch
- Group Microbial Communication, Helmholtz-Centre for Infection Research Braunschweig, Germany
| | - Hui Wang
- Group Microbial Communication, Helmholtz-Centre for Infection Research Braunschweig, Germany
| | - Victoria Michael
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures Braunschweig, Germany
| | - Jörn Petersen
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures Braunschweig, Germany
| | - Bert Engelen
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University of Oldenburg Oldenburg, Germany
| | - Irene Wagner-Döbler
- Group Microbial Communication, Helmholtz-Centre for Infection Research Braunschweig, Germany
| | - Heribert Cypionka
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University of Oldenburg Oldenburg, Germany
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