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Gonzalez JM, Aranda B. Microbial Growth under Limiting Conditions-Future Perspectives. Microorganisms 2023; 11:1641. [PMID: 37512814 PMCID: PMC10383181 DOI: 10.3390/microorganisms11071641] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/02/2023] [Accepted: 06/20/2023] [Indexed: 07/30/2023] Open
Abstract
Microorganisms rule the functioning of our planet and each one of the individual macroscopic living creature. Nevertheless, microbial activity and growth status have always been challenging tasks to determine both in situ and in vivo. Microbial activity is generally related to growth, and the growth rate is a result of the availability of nutrients under adequate or adverse conditions faced by microbial cells in a changing environment. Most studies on microorganisms have been carried out under optimum or near-optimum growth conditions, but scarce information is available about microorganisms at slow-growing states (i.e., near-zero growth and maintenance metabolism). This study aims to better understand microorganisms under growth-limiting conditions. This is expected to provide new perspectives on the functions and relevance of the microbial world. This is because (i) microorganisms in nature frequently face conditions of severe growth limitation, (ii) microorganisms activate singular pathways (mostly genes remaining to be functionally annotated), resulting in a broad range of secondary metabolites, and (iii) the response of microorganisms to slow-growth conditions remains to be understood, including persistence strategies, gene expression, and cell differentiation both within clonal populations and due to the complexity of the environment.
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Affiliation(s)
- Juan M Gonzalez
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, E-41012 Sevilla, Spain
| | - Beatriz Aranda
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, E-41012 Sevilla, Spain
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2
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Ortiz Camargo AR, van Mastrigt O, Bongers RS, Ben-Amor K, Knol J, Abee T, Smid EJ. Quantitative Physiology and Proteome Adaptations of Bifidobacterium breve NRBB57 at Near-Zero Growth Rates. Microbiol Spectr 2023; 11:e0256822. [PMID: 37184421 PMCID: PMC10269484 DOI: 10.1128/spectrum.02568-22] [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: 07/05/2022] [Accepted: 04/26/2023] [Indexed: 05/16/2023] Open
Abstract
In natural environments, nutrients are usually scarce, causing microorganisms to grow slowly while staying metabolically active. These natural conditions can be simulated using retentostat cultivations. The present study describes the physiological and proteome adaptations of the probiotic Bifidobacterium breve NRBB57 from high (0.4 h-1) to near-zero growth rates. Lactose-limited retentostat cultivations were carried out for 21 days in which the bacterial growth rate progressively reduced to 0.00092 h-1, leading to a 3.4-fold reduction of the maintenance energy requirement. Lactose was mainly converted into acetate, formate, and ethanol at high growth rates, while in the retentostat, lactate production increased. Interestingly, the consumption of several amino acids (serine, aspartic acid, and glutamine/arginine) and glycerol increased over time in the retentostat. Morphological changes and viable but nonculturable cells were also observed in the retentostat. Proteomes were compared for all growth rates, revealing a downregulation of ribosomal proteins at near-zero growth rates and an upregulation of proteins involved in the catabolism of alternative energy sources. Finally, we observed induction of the stringent response and stress defense systems. Retentostat cultivations were proven useful to study the physiology of B. breve, mimicking the nutrient scarcity of its complex habitat, the human gut. IMPORTANCE In natural environments, nutrients are usually scarce, causing microorganisms to grow slowly while staying metabolically active. In this study we used retentostat cultivation to investigate how the probiotic Bifidobacterium breve adapts its physiology and proteome under severe nutrient limitation resulting in near-zero growth rates (<0.001 h-1). We showed that the nutrient limitation induced a multifaceted response including stress defense and stringent response, metabolic shifts, and the activation of novel alternative energy-producing pathways.
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Affiliation(s)
| | - Oscar van Mastrigt
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | | | | | - Jan Knol
- Danone Nutricia Research, Utrecht, The Netherlands
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Tjakko Abee
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Eddy J. Smid
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
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3
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Okabe S, Kamigaito A, Kobayashi K. Maintenance power requirements of anammox bacteria "Candidatus Brocadia sinica" and "Candidatus Scalindua sp.". THE ISME JOURNAL 2021; 15:3566-3575. [PMID: 34145389 PMCID: PMC8629980 DOI: 10.1038/s41396-021-01031-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/27/2021] [Accepted: 06/02/2021] [Indexed: 02/05/2023]
Abstract
Little is known about the cell physiology of anammox bacteria growing at extremely low growth rates. Here, "Candidatus Brocadia sinica" and "Candidatus Scalindua sp." were grown in continuous anaerobic membrane bioreactors (MBRs) with complete biomass retention to determine maintenance energy (i.e., power) requirements at near-zero growth rates. After prolonged retentostat cultivations, the specific growth rates (μ) of "Ca. B. sinica" and "Ca. Scalindua sp." decreased to 0.000023 h-1 (doubling time of 1255 days) and 0.000157 h-1 (184 days), respectively. Under these near-zero growth conditions, substrate was continuously utilized to meet maintenance energy demands (me) of 6.7 ± 0.7 and 4.3 ± 0.7 kJ mole of biomass-C-1 h-1 for "Ca. B. sinica" and "Ca. Scalindua sp.", which accorded with the theoretically predicted values of all anaerobic microorganisms (9.7 and 4.4 kJ mole of biomass-C-1 h-1at 37 °C and 28 °C, respectively). These me values correspond to 13.4 × 10-15 and 8.6 × 10-15 watts cell-1 for "Ca. B. sinica" and "Ca. Scalindua sp.", which were five orders of magnitude higher than the basal power limit for natural settings (1.9 × 10-19 watts cells-1). Furthermore, the minimum substrate concentrations required for growth (Smin) were calculated to be 3.69 ± 0.21 and 0.09 ± 0.05 μM NO2- for "Ca. B. sinica" and "Ca. Scalindua sp.", respectively. These results match the evidence that "Ca. Scalindua sp." with lower maintenance power requirement and Smin are better adapted to energy-limited natural environments than "Ca. B. sinica", suggesting the importance of these parameters on ecological niche differentiation in natural environments.
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Affiliation(s)
- Satoshi Okabe
- grid.39158.360000 0001 2173 7691Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Sapporo, Hokkaido, 060-8628 Japan
| | - Atsushi Kamigaito
- grid.39158.360000 0001 2173 7691Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Sapporo, Hokkaido, 060-8628 Japan
| | - Kanae Kobayashi
- grid.39158.360000 0001 2173 7691Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Sapporo, Hokkaido, 060-8628 Japan
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4
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Okabe S, Shafdar AA, Kobayashi K, Zhang L, Oshiki M. Glycogen metabolism of the anammox bacterium "Candidatus Brocadia sinica". THE ISME JOURNAL 2021; 15:1287-1301. [PMID: 33288860 PMCID: PMC8115630 DOI: 10.1038/s41396-020-00850-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 11/03/2020] [Accepted: 11/18/2020] [Indexed: 01/19/2023]
Abstract
Presence of glycogen granules in anaerobic ammonium-oxidizing (anammox) bacteria has been reported so far. However, very little is known about their glycogen metabolism and the exact roles. Here, we studied the glycogen metabolism in "Ca. Brocadia sinica" growing in continuous retentostat cultures with bicarbonate as a carbon source. The effect of the culture growth phase was investigated. During the growing phase, intracellular glycogen content increased up to 32.6 mg-glucose (g-biomass dry wt)-1 while the specific growth rate and ATP/ADP ratio decreased. The accumulated glycogen begun to decrease at the onset of entering the near-zero growth phase and was consumed rapidly when substrates were depleted. This clearly indicates that glycogen was synthesized and utilized as an energy storage. The proteomic analysis revealed that "Ca. B. sinica" synthesized glycogen via three known glycogen biosynthesis pathways and simultaneously degraded during the progress of active anammox, implying that glycogen is being continuously recycled. When cells were starved, a part of stored glycogen was converted to trehalose, a potential stress protectant. This suggests that glycogen serves at least as a primary carbon source of trehalose synthesis for survival. This study provides the first physiological evidence of glycogen metabolism in anammox bacteria and its significance in survival under natural substrate-limited habitat.
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Affiliation(s)
- Satoshi Okabe
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan.
| | - Amrini Amalia Shafdar
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Kanae Kobayashi
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Lei Zhang
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Mamoru Oshiki
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
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5
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Kleerebezem M, Bachmann H, van Pelt-KleinJan E, Douwenga S, Smid EJ, Teusink B, van Mastrigt O. Lifestyle, metabolism and environmental adaptation in Lactococcus lactis. FEMS Microbiol Rev 2021; 44:804-820. [PMID: 32990728 DOI: 10.1093/femsre/fuaa033] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 09/28/2020] [Indexed: 12/14/2022] Open
Abstract
Lactococcus lactis serves as a paradigm organism for the lactic acid bacteria (LAB). Extensive research into the molecular biology, metabolism and physiology of several model strains of this species has been fundamental for our understanding of the LAB. Genomic studies have provided new insights into the species L. lactis, including the resolution of the genetic basis of its subspecies division, as well as the control mechanisms involved in the fine-tuning of growth rate and energy metabolism. In addition, it has enabled novel approaches to study lactococcal lifestyle adaptations to the dairy application environment, including its adjustment to near-zero growth rates that are particularly relevant in the context of cheese ripening. This review highlights various insights in these areas and exemplifies the strength of combining experimental evolution with functional genomics and bacterial physiology research to expand our fundamental understanding of the L. lactis lifestyle under different environmental conditions.
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Affiliation(s)
- Michiel Kleerebezem
- Host-Microbe Interactomics Group, Animal Sciences Department, Wageningen University, De Elst 1, 6708 WD Wageningen, the Netherlands
| | - Herwig Bachmann
- Systems Bioinformatics, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands.,NIZO food research, Kernhemseweg 2, 6718 ZB Ede, the Netherlands
| | - Eunice van Pelt-KleinJan
- Systems Bioinformatics, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands.,TiFN Food & Nutrition, Nieuwe Kanaal 9A, 6709 PA Wageningen, the Netherlands
| | - Sieze Douwenga
- Systems Bioinformatics, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands.,TiFN Food & Nutrition, Nieuwe Kanaal 9A, 6709 PA Wageningen, the Netherlands
| | - Eddy J Smid
- Laboratory of Food Microbiology, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - Bas Teusink
- Systems Bioinformatics, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Oscar van Mastrigt
- Laboratory of Food Microbiology, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
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Dragoš A, Priyadarshini B, Hasan Z, Strube ML, Kempen PJ, Maróti G, Kaspar C, Bose B, Burton BM, Bischofs IB, Kovács ÁT. Pervasive prophage recombination occurs during evolution of spore-forming Bacilli. ISME JOURNAL 2020; 15:1344-1358. [PMID: 33343000 DOI: 10.1038/s41396-020-00854-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/12/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023]
Abstract
Phages are the main source of within-species bacterial diversity and drivers of horizontal gene transfer, but we know little about the mechanisms that drive genetic diversity of these mobile genetic elements (MGEs). Recently, we showed that a sporulation selection regime promotes evolutionary changes within SPβ prophage of Bacillus subtilis, leading to direct antagonistic interactions within the population. Herein, we reveal that under a sporulation selection regime, SPβ recombines with low copy number phi3Ts phage DNA present within the B. subtilis population. Recombination results in a new prophage occupying a different integration site, as well as the spontaneous release of virulent phage hybrids. Analysis of Bacillus sp. strains suggests that SPβ and phi3T belong to a distinct cluster of unusually large phages inserted into sporulation-related genes that are equipped with a spore-related genetic arsenal. Comparison of Bacillus sp. genomes indicates that similar diversification of SPβ-like phages takes place in nature. Our work is a stepping stone toward empirical studies on phage evolution, and understanding the eco-evolutionary relationships between bacteria and their phages. By capturing the first steps of new phage evolution, we reveal striking relationship between survival strategy of bacteria and evolution of their phages.
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Affiliation(s)
- Anna Dragoš
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
| | - B Priyadarshini
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Zahraa Hasan
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Mikael Lenz Strube
- Bacterial Ecophysiology and Biotechnology Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Paul J Kempen
- Department of Health Technology, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Gergely Maróti
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, H-6701, Hungary
| | - Charlotte Kaspar
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | | | - Briana M Burton
- Department of Bacteriology, University of Wisconsin, Madison, WI, 53706, USA
| | - Ilka B Bischofs
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Ákos T Kovács
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
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van Mastrigt O, Egas RA, Lillevang SK, Abee T, Smid EJ. Application of a partial cell recycling chemostat for continuous production of aroma compounds at near-zero growth rates. BMC Res Notes 2019; 12:173. [PMID: 30909948 PMCID: PMC6434626 DOI: 10.1186/s13104-019-4213-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 03/18/2019] [Indexed: 12/22/2022] Open
Abstract
Objective The partial cell recycling chemostat is a modification of the chemostat in which cells are partially recycled towards the bioreactor. This allows using dilution rates higher than the maximum growth rate resulting in higher biomass concentrations and increased process rates. In this study, we demonstrate with a single observation that this system can also be used to study microorganisms at near-zero growth rates and as production system for compounds specific for slow growth, such as those typical for ripened cheese. Results Lactococcus lactis FM03-V2 was cultivated at growth rates between 0.0025 and 0.025 h−1. Detailed analysis of produced aroma compounds revealed that levels of particular compounds were clearly affected by the growth rate within the studied range demonstrating that we can steer the aroma production by controlling the growth rate. With this approach, we also experimentally validated that the maintenance coefficient of this dairy strain decreased at near-zero growth rates (6.4-fold). An exponentially decreasing maintenance coefficient was included in the growth model, enabling accurate prediction of biomass accumulation in the partial cell recycling chemostat. This study demonstrates the potential of partial cell recycling chemostat both as aroma production system at near-zero growth rates and as unique research tool. Electronic supplementary material The online version of this article (10.1186/s13104-019-4213-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Oscar van Mastrigt
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Reinier A Egas
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | | | - Tjakko Abee
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Eddy J Smid
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
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Hausmann B, Pelikan C, Rattei T, Loy A, Pester M. Long-Term Transcriptional Activity at Zero Growth of a Cosmopolitan Rare Biosphere Member. mBio 2019; 10:e02189-18. [PMID: 30755506 PMCID: PMC6372793 DOI: 10.1128/mbio.02189-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/04/2019] [Indexed: 01/05/2023] Open
Abstract
Microbial diversity in the environment is mainly concealed within the rare biosphere (all species with <0.1% relative abundance). While dormancy explains a low-abundance state very well, the mechanisms leading to rare but active microorganisms remain elusive. We used environmental systems biology to genomically and transcriptionally characterize "Candidatus Desulfosporosinus infrequens," a low-abundance sulfate-reducing microorganism cosmopolitan to freshwater wetlands, where it contributes to cryptic sulfur cycling. We obtained its near-complete genome by metagenomics of acidic peat soil. In addition, we analyzed anoxic peat soil incubated under in situ-like conditions for 50 days by Desulfosporosinus-targeted qPCR and metatranscriptomics. The Desulfosporosinus population stayed at a constant low abundance under all incubation conditions, averaging 1.2 × 106 16S rRNA gene copies per cm³ soil. In contrast, transcriptional activity of "Ca. Desulfosporosinus infrequens" increased at day 36 by 56- to 188-fold when minor amendments of acetate, propionate, lactate, or butyrate were provided with sulfate, compared to the no-substrate-control. Overall transcriptional activity was driven by expression of genes encoding ribosomal proteins, energy metabolism, and stress response but not by expression of genes encoding cell growth-associated processes. Since our results did not support growth of these highly active microorganisms in terms of biomass increase or cell division, they had to invest their sole energy for maintenance, most likely counterbalancing acidic pH conditions. This finding explains how a rare biosphere member can contribute to a biogeochemically relevant process while remaining in a zero-growth state over a period of 50 days.IMPORTANCE The microbial rare biosphere represents the largest pool of biodiversity on Earth and constitutes, in sum of all its members, a considerable part of a habitat's biomass. Dormancy or starvation is typically used to explain the persistence of low-abundance microorganisms in the environment. We show that a low-abundance microorganism can be highly transcriptionally active while remaining in a zero-growth state for at least 7 weeks. Our results provide evidence that this zero growth at a high cellular activity state is driven by maintenance requirements. We show that this is true for a microbial keystone species, in particular a cosmopolitan but permanently low-abundance sulfate-reducing microorganism in wetlands that is involved in counterbalancing greenhouse gas emissions. In summary, our results provide an important step forward in understanding time-resolved activities of rare biosphere members relevant for ecosystem functions.
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Affiliation(s)
- Bela Hausmann
- Research Network Chemistry meets Microbiology, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Claus Pelikan
- Research Network Chemistry meets Microbiology, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Thomas Rattei
- Research Network Chemistry meets Microbiology, Department of Microbiology and Ecosystem Science, Division of Computational Systems Biology, University of Vienna, Vienna, Austria
| | - Alexander Loy
- Research Network Chemistry meets Microbiology, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Michael Pester
- Department of Biology, University of Konstanz, Konstanz, Germany
- Department of Microorganisms, Leibniz Institute DSMZ, Braunschweig, Germany
- Institute of Microbiology, Technical University of Braunschweig, Braunschweig, Germany
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9
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Quantitative physiology and aroma formation of a dairy Lactococcus lactis at near-zero growth rates. Food Microbiol 2018. [DOI: 10.1016/j.fm.2018.01.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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10
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Liu D, Mao Z, Guo J, Wei L, Ma H, Tang Y, Chen T, Wang Z, Zhao X. Construction, Model-Based Analysis, and Characterization of a Promoter Library for Fine-Tuned Gene Expression in Bacillus subtilis. ACS Synth Biol 2018; 7:1785-1797. [PMID: 29944832 DOI: 10.1021/acssynbio.8b00115] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Promoters are among the most-important and most-basic tools for the control of metabolic pathways. However, previous research mainly focused on the screening and characterization of some native promoters in Bacillus subtilis. To develop a broadly applicable promoter system for this important platform organism, we created a de novo synthetic promoter library (SPL) based on consensus sequences by analyzing the microarray transcriptome data of B. subtilis 168. A total of 214 potential promoters spanning a gradient of strengths was isolated and characterized by a green fluorescence assay. Among these, a detailed intensity analysis was conducted on nine promoters with different strengths by reverse-transcription polymerase chain reaction (RT-PCR) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Furthermore, reconstructed promoters and promoter cassettes (tandem promoter cluster) were designed via statistical model-based analysis and tandem dual promoters, which showed strength that was increased 1.2- and 2.77-fold compared to that of promoter P43, respectively. Finally, the SPL was employed in the production of inosine and acetoin by repressing and over-expressing the relevant metabolic pathways, yielding a 700% and 44% increase relative to the respective control strains. This is the first report of a de novo synthetic promoter library for B. subtilis, which is independent of any native promoter. The strategy of improving and fine-tuning promoter strengths will contribute to future metabolic engineering and synthetic biology projects in B. subtilis.
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Affiliation(s)
| | - Zhitao Mao
- Key Laboratory of System Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | | | | | - Hongwu Ma
- Key Laboratory of System Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yajie Tang
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan 430068, China
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11
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Orsi WD. Ecology and evolution of seafloor and subseafloor microbial communities. Nat Rev Microbiol 2018; 16:671-683. [DOI: 10.1038/s41579-018-0046-8] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Zhang D, Strawn M, Novak JT, Wang ZW. Kinetic modeling of the effect of solids retention time on methanethiol dynamics in anaerobic digestion. WATER RESEARCH 2018; 138:301-311. [PMID: 29614458 DOI: 10.1016/j.watres.2018.03.035] [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: 11/14/2017] [Revised: 03/11/2018] [Accepted: 03/13/2018] [Indexed: 06/08/2023]
Abstract
The highly volatile methanethiol (MT) with an extremely low odor threshold and distinctive putrid smell is often identified as a major odorous compound generated under anaerobic conditions. As an intermediate compound in the course of anaerobic digestion, the extent of MT emission is closely related to the time of anaerobic reaction. In this study, lab-scale anaerobic digesters were operated at solids retention time (SRTs) of 15, 20, 25, 30, 40 and 50 days to investigate the effect of SRT on MT emission. The experimental results demonstrated a bell-shaped curve of MT emission versus SRT with a peak around 20 days SRT. In order to understand this SRT effect, a kinetic model was developed to describe MT production and utilization dynamics in the course of anaerobic digestion and calibrated with the experimental results collected from this study. The model outcome revealed that the high protein content in the feed sludge together with the large maintenance coefficient of MT fermenters are responsible for the peak MT emission emergence in the range of typical SRT used for anaerobic digestion. A further analysis of the kinetic model shows that it can be extensively simplified with reasonable approximation to a form that anaerobic digestion practitioners could easily use to predict the MT and SRT relationship.
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Affiliation(s)
- Dian Zhang
- Occoquan Laboratory, Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William Street, Manassas, VA 20110, USA
| | - Mary Strawn
- Arlington County Water Pollution Control Bureau, 3402 S Glebe Rd, Arlington, VA 22202, USA
| | - John T Novak
- Occoquan Laboratory, Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William Street, Manassas, VA 20110, USA
| | - Zhi-Wu Wang
- Occoquan Laboratory, Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William Street, Manassas, VA 20110, USA.
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13
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Marozava S, Vargas-López R, Tian Y, Merl-Pham J, Braster M, Meckenstock RU, Smidt H, Röling WFM, Westerhoff HV. Metabolic flexibility of a prospective bioremediator: Desulfitobacterium hafniense Y51 challenged in chemostats. Environ Microbiol 2018; 20:2652-2669. [PMID: 29921035 DOI: 10.1111/1462-2920.14295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 05/19/2018] [Indexed: 11/30/2022]
Abstract
Desulfitobacterium hafniense Y51 has been widely used in investigations of perchloroethylene (PCE) biodegradation, but limited information exists on its other physiological capabilities. We investigated how D. hafniense Y51 confronts the debilitating limitations of not having enough electron donor (lactate), or electron acceptor (fumarate) during cultivation in chemostats. The residual concentrations of the substrates supplied in excess were much lower than expected. Transcriptomics, proteomics and fluxomics were integrated to investigate how this phenomenon was regulated. Through diverse regulation at both transcriptional and translational levels, strain Y51 turned to fermenting the excess lactate and disproportionating the excess fumarate under fumarate- and lactate-limiting conditions respectively. Genes and proteins related to the utilization of a variety of alternative electron donors and acceptors absent from the medium were induced, apparently involving the Wood-Ljungdahl pathway. Through this metabolic flexibility, D. hafniense Y51 may be able to switch between different metabolic capabilities under limiting conditions.
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Affiliation(s)
- Sviatlana Marozava
- Institute of Groundwater Ecology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Raquel Vargas-López
- Molecular Cell Physiology, Faculty of Science, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, The Netherlands
| | - Ye Tian
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Juliane Merl-Pham
- Core Facility Proteomics, Helmholtz Zentrum München, Heidemannstraße 1, 80939, München, Germany
| | - Martin Braster
- Molecular Cell Physiology, Faculty of Science, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, The Netherlands
| | - Rainer U Meckenstock
- Institute of Groundwater Ecology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Wilfred F M Röling
- Molecular Cell Physiology, Faculty of Science, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, The Netherlands
| | - Hans V Westerhoff
- Molecular Cell Physiology, Faculty of Science, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, The Netherlands.,Synthetic Systems Biology, SILS, University of Amsterdam, Amsterdam, The Netherlands.,Manchester Centre for Integrative Systems Biology, School of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
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14
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Eymard-Vernain E, Lelong C, Pradas Del Real AE, Soulas R, Bureau S, Tardillo Suarez V, Gallet B, Proux O, Castillo-Michel H, Sarret G. Impact of a Model Soil Microorganism and of Its Secretome on the Fate of Silver Nanoparticles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:71-78. [PMID: 29211460 DOI: 10.1021/acs.est.7b04071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Sulfidation is a key process for silver nanoparticles released from consumer products in the environment. This study focuses on the impact of a model soil microorganism, Bacillus subtilis, on the fate of pristine and already sulfidized Ag-NPs. The nanoparticles were incubated with the initial growth medium, isolated secretome, and living bacteria, and characterized for their size and morphology, agglomeration state, structure, and Ag speciation. No Ag internalization or sorption on the cell wall was detected. A partial sulfidation, leading to an Ag-Ag2S core-shell structure, was observed in the presence of the secretome, and the rate limiting step of the reaction was the oxidation of Ag0, and it was favored near the crystal dislocations. The sulfidation was complete in the presence of the living bacteria and followed an indirect pathway. Both crystalline Ag2S and amorphous Ag2S and/or Ag-thiol were identified. At the opposite, the bacteria had no impact on Ag2S. These results suggest that microorganisms participate in the sulfidation of Ag-NPs in aerobic systems such as unsaturated soils, and thus affect the bioavailability of Ag. It is important to take these transformations into account during exposure experiments, since they drastically change the exposure conditions. Finally, the secretome of B. subtilis might be used for the green synthesis of Ag-Ag2S core-shell nanoparticles.
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Affiliation(s)
- Elise Eymard-Vernain
- ISTerre (Institut des Sciences de la Terre), Université Grenoble Alpes, CNRS , CS 40700 Grenoble, France
- Université Grenoble Alpes , CEA Grenoble, Lab Chim & Biol Met, UMR CNRS CEA UJF, ProMD Team, BIG, CS 40700 Grenoble, France
| | - Cécile Lelong
- Université Grenoble Alpes , CEA Grenoble, Lab Chim & Biol Met, UMR CNRS CEA UJF, ProMD Team, BIG, CS 40700 Grenoble, France
| | - Ana-Elena Pradas Del Real
- ISTerre (Institut des Sciences de la Terre), Université Grenoble Alpes, CNRS , CS 40700 Grenoble, France
- ID21, ESRF-The European Synchrotron , CS 40220 Grenoble, France
| | - Romain Soulas
- LITEN , CEA Grenoble, 17 Rue des Martyrs, F-38054 Grenoble, France
| | - Sarah Bureau
- ISTerre (Institut des Sciences de la Terre), Université Grenoble Alpes, CNRS , CS 40700 Grenoble, France
| | | | - Benoit Gallet
- Université Grenoble Alpes , CEA, CNRS, IBS, F-38000 Grenoble, France
| | - Olivier Proux
- Observatoire des Sciences de l'Univers de Grenoble (OSUG), UMR CNRS 832, Université Grenoble-Alpes , CS 40700 Grenoble, France
- BM30B/CRG-FAME, ESRF, Polygone Scientifique Louis Néel , 71 avenue des Martyrs, 38000 Grenoble, France
| | | | - Géraldine Sarret
- ISTerre (Institut des Sciences de la Terre), Université Grenoble Alpes, CNRS , CS 40700 Grenoble, France
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15
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Singh R, Miriyala SS, Giri L, Mitra K, Kareenhalli VV. Identification of unstructured model for subtilin production through Bacillus subtilis using hybrid genetic algorithm. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.06.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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16
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De novo evolved interference competition promotes the spread of biofilm defectors. Nat Commun 2017; 8:15127. [PMID: 28462927 PMCID: PMC5418572 DOI: 10.1038/ncomms15127] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 03/02/2017] [Indexed: 11/16/2022] Open
Abstract
Biofilms are social entities where bacteria live in tightly packed agglomerations, surrounded by self-secreted exopolymers. Since production of exopolymers is costly and potentially exploitable by non-producers, mechanisms that prevent invasion of non-producing mutants are hypothesized. Here we study long-term dynamics and evolution in Bacillus subtilis biofilm populations consisting of wild-type (WT) matrix producers and mutant non-producers. We show that non-producers initially fail to incorporate into biofilms formed by the WT cells, resulting in 100-fold lower final frequency compared to the WT. However, this is modulated in a long-term scenario, as non-producers evolve the ability to better incorporate into biofilms, thereby slightly decreasing the productivity of the whole population. Detailed molecular analysis reveals that the unexpected shift in the initially stable biofilm is coupled with newly evolved phage-mediated interference competition. Our work therefore demonstrates how collective behaviour can be disrupted as a result of rapid adaptation through mobile genetic elements. The production of secreted polymers in bacterial biofilms is costly, and therefore mechanisms preventing invasion of non-producing mutants are hypothesized. Here, the authors show that non-producers can evolve the ability to better incorporate into biofilms via phage-mediated interference.
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17
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Morrissey EM, Mau RL, Schwartz E, McHugh TA, Dijkstra P, Koch BJ, Marks JC, Hungate BA. Bacterial carbon use plasticity, phylogenetic diversity and the priming of soil organic matter. ISME JOURNAL 2017; 11:1890-1899. [PMID: 28387774 DOI: 10.1038/ismej.2017.43] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/06/2017] [Accepted: 02/14/2017] [Indexed: 12/26/2022]
Abstract
Microorganisms perform most decomposition on Earth, mediating carbon (C) loss from ecosystems, and thereby influencing climate. Yet, how variation in the identity and composition of microbial communities influences ecosystem C balance is far from clear. Using quantitative stable isotope probing of DNA, we show how individual bacterial taxa influence soil C cycling following the addition of labile C (glucose). Specifically, we show that increased decomposition of soil C in response to added glucose (positive priming) occurs as a phylogenetically diverse group of taxa, accounting for a large proportion of the bacterial community, shift toward additional soil C use for growth. Our findings suggest that many microbial taxa exhibit C use plasticity, as most taxa altered their use of glucose and soil organic matter depending upon environmental conditions. In contrast, bacteria that exhibit other responses to glucose (reduced growth or reliance on glucose for additional growth) clustered strongly by phylogeny. These results suggest that positive priming is likely the prototypical response of bacteria to sustained labile C addition, consistent with the widespread occurrence of the positive priming effect in nature.
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Affiliation(s)
- Ember M Morrissey
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, USA
| | - Rebecca L Mau
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Theresa A McHugh
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Colorado Mesa University, Grand Junction, CO, USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Benjamin J Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Jane C Marks
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
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18
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Song Y, Nikoloff JM, Fu G, Chen J, Li Q, Xie N, Zheng P, Sun J, Zhang D. Promoter Screening from Bacillus subtilis in Various Conditions Hunting for Synthetic Biology and Industrial Applications. PLoS One 2016; 11:e0158447. [PMID: 27380260 PMCID: PMC4933340 DOI: 10.1371/journal.pone.0158447] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 06/16/2016] [Indexed: 11/24/2022] Open
Abstract
The use of Bacillus subtilis in synthetic biology and metabolic engineering is highly desirable to take advantage of the unique metabolic pathways present in this organism. To do this, an evaluation of B. subtilis’ intrinsic biological parts is required to determine the best strategies to accurately regulate metabolic circuits and expression of target proteins. The strengths of promoter candidates were evaluated by measuring relative fluorescence units of a green fluorescent protein reporter, integrated into B. subtilis’ chromosome. A total of 84 predicted promoter sequences located upstream of different classes of proteins including heat shock proteins, cell-envelope proteins, and proteins resistant against toxic metals (based on similarity) and other kinds of genes were tested. The expression levels measured ranged from 0.0023 to 4.53-fold of the activity of the well-characterized strong promoter P43. No significant shifts were observed when strains, carrying different promoter candidates, were cultured at high temperature or in media with ethanol, but some strains showed increased activity when cultured under high osmotic pressure. Randomly selected promoter candidates were tested and found to activate transcription of thermostable β-galactosidase (bgaB) at a similar level, implying the ability of these sequences to function as promoter elements in multiple genetic contexts. In addition, selected promoters elevated the final production of both cytoplasmic bgaB and secreted protein α-amylase to about fourfold and twofold, respectively. The generated data allows a deeper understanding of B. subtilis’ metabolism and will facilitate future work to develop this organism for synthetic biology.
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Affiliation(s)
- Yafeng Song
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Jonas M Nikoloff
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Gang Fu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Jingqi Chen
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Qinggang Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Nengzhong Xie
- National Engineering Research Center for Non-food Biorefinery, State Key Laboratory of Non-food Biomass Energy and Enzyme Technology, Nanning 5300074, P. R. China
- Guangxi Biomass Industrialization Engineering Institute, Guangxi Academy of Sciences, Nanning 530007, P. R. China
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
| | - Dawei Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
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19
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Peters JM, Colavin A, Shi H, Czarny TL, Larson MH, Wong S, Hawkins JS, Lu CHS, Koo BM, Marta E, Shiver AL, Whitehead EH, Weissman JS, Brown ED, Qi LS, Huang KC, Gross CA. A Comprehensive, CRISPR-based Functional Analysis of Essential Genes in Bacteria. Cell 2016; 165:1493-1506. [PMID: 27238023 PMCID: PMC4894308 DOI: 10.1016/j.cell.2016.05.003] [Citation(s) in RCA: 456] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/28/2016] [Accepted: 04/20/2016] [Indexed: 12/28/2022]
Abstract
Essential gene functions underpin the core reactions required for cell viability, but their contributions and relationships are poorly studied in vivo. Using CRISPR interference, we created knockdowns of every essential gene in Bacillus subtilis and probed their phenotypes. Our high-confidence essential gene network, established using chemical genomics, showed extensive interconnections among distantly related processes and identified modes of action for uncharacterized antibiotics. Importantly, mild knockdown of essential gene functions significantly reduced stationary-phase survival without affecting maximal growth rate, suggesting that essential protein levels are set to maximize outgrowth from stationary phase. Finally, high-throughput microscopy indicated that cell morphology is relatively insensitive to mild knockdown but profoundly affected by depletion of gene function, revealing intimate connections between cell growth and shape. Our results provide a framework for systematic investigation of essential gene functions in vivo broadly applicable to diverse microorganisms and amenable to comparative analysis.
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Affiliation(s)
- Jason M Peters
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | | | - Handuo Shi
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Tomasz L Czarny
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 3Z5, Canada; Michael G. DeGroote Institute of Infectious Disease Research, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Matthew H Larson
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute for Quantitative Biomedical Research, San Francisco, CA 94158, USA; Center for RNA Systems Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Spencer Wong
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - John S Hawkins
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Biophysics Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Candy H S Lu
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Byoung-Mo Koo
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Elizabeth Marta
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Anthony L Shiver
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Biophysics Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Evan H Whitehead
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute for Quantitative Biomedical Research, San Francisco, CA 94158, USA; UCSF Center for Systems and Synthetic Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute for Quantitative Biomedical Research, San Francisco, CA 94158, USA; Center for RNA Systems Biology, University of California, Berkeley, Berkeley, CA 94720, USA; UCSF Center for Systems and Synthetic Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 3Z5, Canada; Michael G. DeGroote Institute of Infectious Disease Research, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Lei S Qi
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA; ChEM-H, Stanford University, Stanford, CA 94305, USA.
| | - Kerwyn Casey Huang
- Biophysics Program, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; School of Medicine, Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, USA.
| | - Carol A Gross
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA.
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20
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Physiological and Transcriptional Responses of Different Industrial Microbes at Near-Zero Specific Growth Rates. Appl Environ Microbiol 2015; 81:5662-70. [PMID: 26048933 DOI: 10.1128/aem.00944-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The current knowledge of the physiology and gene expression of industrially relevant microorganisms is largely based on laboratory studies under conditions of rapid growth and high metabolic activity. However, in natural ecosystems and industrial processes, microbes frequently encounter severe calorie restriction. As a consequence, microbial growth rates in such settings can be extremely slow and even approach zero. Furthermore, uncoupling microbial growth from product formation, while cellular integrity and activity are maintained, offers perspectives that are economically highly interesting. Retentostat cultures have been employed to investigate microbial physiology at (near-)zero growth rates. This minireview compares information from recent physiological and gene expression studies on retentostat cultures of the industrially relevant microorganisms Lactobacillus plantarum, Lactococcus lactis, Bacillus subtilis, Saccharomyces cerevisiae, and Aspergillus niger. Shared responses of these organisms to (near-)zero growth rates include increased stress tolerance and a downregulation of genes involved in protein synthesis. Other adaptations, such as changes in morphology and (secondary) metabolite production, were species specific. This comparison underlines the industrial and scientific significance of further research on microbial (near-)zero growth physiology.
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21
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Genome-wide transcriptional responses to carbon starvation in nongrowing Lactococcus lactis. Appl Environ Microbiol 2015; 81:2554-61. [PMID: 25636846 DOI: 10.1128/aem.03748-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This paper describes the transcriptional adaptations of nongrowing, retentostat cultures of Lactococcus lactis to starvation. Near-zero-growth cultures (μ = 0.0001 h(-1)) obtained by extended retentostat cultivation were exposed to starvation by termination of the medium supply for 24 h, followed by a recovery period of another 24 h by reinitiating the medium supply to the retentostat culture. During starvation, the viability of the culture was largely retained, and the expression of genes involved in transcription and translational machineries, cell division, and cell membrane energy metabolism was strongly repressed. Expression of these genes was largely recovered following the reinitiation of the medium supply. Starvation triggered the elevated expression of genes associated with synthesis of branched-chain amino acids, histidine, purine, and riboflavin. The expression of these biosynthesis genes was found to remain at an elevated level after reinitiation of the medium supply. In addition, starvation induced the complete gene set predicted to be involved in natural competence in L. lactis KF147, and the elevated expression of these genes was sustained during the subsequent recovery period, but our attempts to experimentally demonstrate natural transformation in these cells failed. Mining the starvation response gene set identified a conserved cis-acting element that resembles the lactococcal CodY motif in the upstream regions of genes associated with transcription and translational machineries, purine biosynthesis, and natural transformation in L. lactis, suggesting a role for CodY in the observed transcriptome adaptations to starvation in nongrowing cells.
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