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Bai C, Cai Y, Sun T, Li G, Wang W, Wong PK, An T. Mechanism of antibiotic resistance spread during sub-lethal ozonation of antibiotic-resistant bacteria with different resistance targets. WATER RESEARCH 2024; 259:121837. [PMID: 38810347 DOI: 10.1016/j.watres.2024.121837] [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: 02/11/2024] [Revised: 05/16/2024] [Accepted: 05/23/2024] [Indexed: 05/31/2024]
Abstract
The increase and spread of antibiotic-resistant bacteria (ARB) in aquatic environments and the dissemination of antibiotic resistance genes (ARGs) greatly impact environmental and human health. It is necessary to understand the mechanism of action of ARB and ARGs to formulate measures to solve this problem. This study aimed to determine the mechanism of antibiotic resistance spread during sub-lethal ozonation of ARB with different antibiotic resistance targets, including proteins, cell walls, and cell membranes. ARB conjugation and transformation frequencies increased after exposure to 0-1.0 mg/L ozone for 10 min. During sub-lethal ozonation, compared with control groups not stimulated by ozone, the conjugative transfer frequencies of E. coli DH5α (CTX), E. coli DH5α (MCR), and E. coli DH5α (GEN) increased by 1.35-2.02, 1.13-1.58, and 1.32-2.12 times, respectively; the transformation frequencies of E. coli DH5α (MCR) and E. coli DH5α (GEN) increased by 1.49-3.02 and 1.45-1.92 times, respectively. When target inhibitors were added, the conjugative transfer frequencies of antibiotics targeting cell wall and membrane synthesis decreased 0.59-0.75 and 0.43-0.76 times, respectively, while that for those targeting protein synthesis increased by 1-1.38 times. After inhibitor addition, the transformation frequencies of bacteria resistant to antibiotics targeting the cell membrane and proteins decreased by 0.76-0.89 and 0.69-0.78 times, respectively. Cell morphology, cell membrane permeability, reactive oxygen species, and antioxidant enzymes changed with different ozone concentrations. Expression of most genes related to regulating different antibiotic resistance targets was up-regulated when bacteria were exposed to sub-lethal ozonation, further confirming the target genes playing a crucial role in the inactivation of different target bacteria. These results will help guide the careful utilization of ozonation for bacterial inactivation, providing more detailed reference information for ozonation oxidation treatment of ARB and ARGs in aquatic environments.
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Affiliation(s)
- Conglin Bai
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development (Department of Education), School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Yiwei Cai
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development (Department of Education), School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Tong Sun
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development (Department of Education), School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Guiying Li
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development (Department of Education), School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Wanjun Wang
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development (Department of Education), School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Po Keung Wong
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development (Department of Education), School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Taicheng An
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development (Department of Education), School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
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Hong J, He H, Xu Y, Wang S, Luo C. An integrative temperature-controlled microfluidic system for budding yeast heat shock response analysis at the single-cell level. LAB ON A CHIP 2024; 24:3658-3667. [PMID: 38915274 DOI: 10.1039/d4lc00313f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Cells can respond and adapt to complex forms of environmental change. Budding yeast is widely used as a model system for these stress response studies. In these studies, the precise control of the environment with high temporal resolution is most important. However, there is a lack of single-cell research platforms that enable precise control of the temperature and form of cell growth. This has hindered our understanding of cellular coping strategies in the face of diverse forms of temperature change. Here, we developed a novel temperature-controlled microfluidic platform that integrates a microheater (using liquid metal) and a thermocouple (liquid metal vs. conductive PDMS) on a chip. Three forms of temperature changes (step, gradient, and periodical oscillations) were realized by automated equipment. The platform has the advantages of low cost and a simple fabrication process. Moreover, we investigated the nuclear entry and exit behaviors of the transcription factor Msn2 in yeast in response to heat stress (37 °C) with different heating modes. The feasibility of this temperature-controlled platform for studying the protein dynamic behavior of yeast cells was demonstrated.
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Affiliation(s)
- Jie Hong
- The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China.
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Hao He
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang, China
| | - Yinjia Xu
- The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China.
| | - Shujing Wang
- The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China.
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Chunxiong Luo
- The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China.
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang, China
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3
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Jashnsaz H, Neuert G. Phenotypic consequences of logarithmic signaling in MAPK stress response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570188. [PMID: 38106069 PMCID: PMC10723343 DOI: 10.1101/2023.12.05.570188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
How cells respond to dynamic environmental changes is crucial for understanding fundamental biological processes and cell physiology. In this study, we developed an experimental and quantitative analytical framework to explore how dynamic stress gradients that change over time regulate cellular volume, signaling activation, and growth phenotypes. Our findings reveal that gradual stress conditions substantially enhance cell growth compared to conventional acute stress. This growth advantage correlates with a minimal reduction in cell volume dependent on the dynamic of stress. We explain the growth phenotype with our finding of a logarithmic signal transduction mechanism in the yeast Mitogen-Activated Protein Kinase (MAPK) osmotic stress response pathway. These insights into the interplay between gradual environments, cell volume change, dynamic cell signaling, and growth, advance our understanding of fundamental cellular processes in gradual stress environments.
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Affiliation(s)
- Hossein Jashnsaz
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232 USA
| | - Gregor Neuert
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232 USA
- Lead Contact
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Loman TE, Locke JCW. The σB alternative sigma factor circuit modulates noise to generate different types of pulsing dynamics. PLoS Comput Biol 2023; 19:e1011265. [PMID: 37540712 PMCID: PMC10431680 DOI: 10.1371/journal.pcbi.1011265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 08/16/2023] [Accepted: 06/12/2023] [Indexed: 08/06/2023] Open
Abstract
Single-cell approaches are revealing a high degree of heterogeneity, or noise, in gene expression in isogenic bacteria. How gene circuits modulate this noise in gene expression to generate robust output dynamics is unclear. Here we use the Bacillus subtilis alternative sigma factor σB as a model system for understanding the role of noise in generating circuit output dynamics. σB controls the general stress response in B. subtilis and is activated by a range of energy and environmental stresses. Recent single-cell studies have revealed that the circuit can generate two distinct outputs, stochastic pulsing and a single pulse response, but the conditions under which each response is generated are under debate. We implement a stochastic mathematical model of the σB circuit to investigate this and find that the system's core circuit can generate both response types. This is despite one response (stochastic pulsing) being stochastic in nature, and the other (single response pulse) being deterministic. We demonstrate that the main determinant for whichever response is generated is the degree with which the input pathway activates the core circuit, although the noise properties of the input pathway also biases the system towards one or the other type of output. Thus, our work shows how stochastic modelling can reveal the mechanisms behind non-intuitive gene circuit output dynamics.
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Affiliation(s)
- Torkel E. Loman
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - James C. W. Locke
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
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Thiemicke A, Neuert G. Rate thresholds in cell signaling have functional and phenotypic consequences in non-linear time-dependent environments. Front Cell Dev Biol 2023; 11:1124874. [PMID: 37025183 PMCID: PMC10072286 DOI: 10.3389/fcell.2023.1124874] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/08/2023] [Indexed: 04/08/2023] Open
Abstract
All cells employ signal transduction pathways to respond to physiologically relevant extracellular cytokines, stressors, nutrient levels, hormones, morphogens, and other stimuli that vary in concentration and rate in healthy and diseased states. A central unsolved fundamental question in cell signaling is whether and how cells sense and integrate information conveyed by changes in the rate of extracellular stimuli concentrations, in addition to the absolute difference in concentration. We propose that different environmental changes over time influence cell behavior in addition to different signaling molecules or different genetic backgrounds. However, most current biomedical research focuses on acute environmental changes and does not consider how cells respond to environments that change slowly over time. As an example of such environmental change, we review cell sensitivity to environmental rate changes, including the novel mechanism of rate threshold. A rate threshold is defined as a threshold in the rate of change in the environment in which a rate value below the threshold does not activate signaling and a rate value above the threshold leads to signal activation. We reviewed p38/Hog1 osmotic stress signaling in yeast, chemotaxis and stress response in bacteria, cyclic adenosine monophosphate signaling in Amoebae, growth factors signaling in mammalian cells, morphogen dynamics during development, temporal dynamics of glucose and insulin signaling, and spatio-temproral stressors in the kidney. These reviewed examples from the literature indicate that rate thresholds are widespread and an underappreciated fundamental property of cell signaling. Finally, by studying cells in non-linear environments, we outline future directions to understand cell physiology better in normal and pathophysiological conditions.
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Affiliation(s)
- Alexander Thiemicke
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, United States
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, United States
| | - Gregor Neuert
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, United States
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, United States
- Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, TN, United States
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, United States
- *Correspondence: Gregor Neuert,
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6
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Abstract
The ability of bacteria to respond to changes in their environment is critical to their survival, allowing them to withstand stress, form complex communities, and induce virulence responses during host infection. A remarkable feature of many of these bacterial responses is that they are often variable across individual cells, despite occurring in an isogenic population exposed to a homogeneous environmental change, a phenomenon known as phenotypic heterogeneity. Phenotypic heterogeneity can enable bet-hedging or division of labor strategies that allow bacteria to survive fluctuating conditions. Investigating the significance of phenotypic heterogeneity in environmental transitions requires dynamic, single-cell data. Technical advances in quantitative single-cell measurements, imaging, and microfluidics have led to a surge of publications on this topic. Here, we review recent discoveries on single-cell bacterial responses to environmental transitions of various origins and complexities, from simple diauxic shifts to community behaviors in biofilm formation to virulence regulation during infection. We describe how these studies firmly establish that this form of heterogeneity is prevalent and a conserved mechanism by which bacteria cope with fluctuating conditions. We end with an outline of current challenges and future directions for the field. While it remains challenging to predict how an individual bacterium will respond to a given environmental input, we anticipate that capturing the dynamics of the process will begin to resolve this and facilitate rational perturbation of environmental responses for therapeutic and bioengineering purposes.
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Bacillus subtilis Stressosome Sensor Protein Sequences Govern the Ability To Distinguish among Environmental Stressors and Elicit Different σ B Response Profiles. mBio 2022; 13:e0200122. [PMID: 36409125 PMCID: PMC9765535 DOI: 10.1128/mbio.02001-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bacteria use a variety of systems to sense stress and mount an appropriate response to ensure fitness and survival. Bacillus subtilis uses stressosomes-cytoplasmic multiprotein complexes-to sense environmental stressors and enact the general stress response by activating the alternative sigma factor σB. Each stressosome includes 40 RsbR proteins, representing four paralogous (RsbRA, RsbRB, RsbRC, and RsbRD) putative stress sensors. Population-level analyses suggested that the RsbR paralogs are largely redundant, while our prior work using microfluidics-coupled fluorescence microscopy uncovered differences among the RsbR paralogs' σB response profiles with respect to timing and intensity when facing an identical stressor. Here, we use a similar approach to address the question of whether the σB responses mediated by each paralog differ in the presence of different environmental stressors: can they distinguish among stressors? Wild-type cells (with all four paralogs) and RsbRA-only cells activate σB with characteristic transient response timing irrespective of stressor but show various response magnitudes. However, cells with other individual RsbR paralogs show distinct timing and magnitude in their responses to ethanol, salt, oxidative, and acid stress, implying that RsbR proteins can distinguish among stressors. Experiments with hybrid fusion proteins comprising the N-terminal half of one paralog and the C-terminal half of another argue that the N-terminal identity influences response magnitude and that determinants in both halves of RsbRA are important for its stereotypical transient σB response timing. IMPORTANCE Bacterial survival depends on appropriate responses to diverse stressors. The general stress-response system in the environmental model bacterium Bacillus subtilis is constantly poised for an immediate response and uses unusual stress-sensing protein complexes called stressosomes. Stressosomes typically contain four different types of putative sensing protein. We asked whether each type of sensor has a distinct role in mediating response dynamics to different environmental stressors. We find that one sensor type always mediates a transient response, while the others show distinct response magnitude and timing to different stressors. We also find that a transient response is exceptional, as several engineered hybrid proteins did not show strong transient responses. Our work reveals functional distinctions among subunits of the stressosome complex and represents a step toward understanding how the general stress response of B. subtilis ensures its survival in natural environmental settings.
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Kuwabara S, Landers ER, Fisher DJ. Impact of nutrients on the function of the chlamydial Rsb partner switching mechanism. Pathog Dis 2022; 80:6831632. [PMID: 36385643 DOI: 10.1093/femspd/ftac044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/27/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022] Open
Abstract
The obligate intracellular bacterial pathogen Chlamydia trachomatis is a leading cause of sexually transmitted infections and infectious blindness. Chlamydia undergo a biphasic developmental cycle alternating between the infectious elementary body (EB) and the replicative reticulate body (RB). The molecular mechanisms governing RB growth and RB-EB differentiation are unclear. We hypothesize that the bacterium senses host cell and bacterial energy levels and metabolites to ensure that development and growth coincide with nutrient availability. We predict that a partner switching mechanism (PSM) plays a key role in the sensing and response process acting as a molecular throttle sensitive to metabolite levels. Using purified wild type and mutant PSM proteins, we discovered that metal type impacts enzyme activity and the substrate specificity of RsbU and that RsbW prefers ATP over GTP as a phosphate donor. Immunoblotting analysis of RsbV1/V2 demonstrated the presence of both proteins beyond 20 hours post infection and we observed that an RsbV1-null strain has a developmental delay and exhibits differential growth attenuation in response to glucose levels. Collectively, our data support that the PSM regulates growth in response to metabolites and further defines biochemical features governing PSM-component interactions which could help in the development of novel PSM-targeted therapeutics.
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Affiliation(s)
- Shiomi Kuwabara
- Molecular Biology, Microbiology and Biochemistry Graduate Program, Southern Illinois University, Carbondale, IL 62901, United States
| | - Evan R Landers
- Molecular Biology, Microbiology and Biochemistry Graduate Program, Southern Illinois University, Carbondale, IL 62901, United States
| | - Derek J Fisher
- Molecular Biology, Microbiology and Biochemistry Graduate Program, Southern Illinois University, Carbondale, IL 62901, United States.,School of Biological Sciences, Southern Illinois University, Carbondale, IL 62901, United States
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Bairoliya S, Goel A, Mukherjee M, Koh Zhi Xiang J, Cao B. Monochloramine Induces Release of DNA and RNA from Bacterial Cells: Quantification, Sequencing Analyses, and Implications. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15791-15804. [PMID: 36215406 DOI: 10.1021/acs.est.2c06632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Monochloramine (MCA) is a widely used secondary disinfectant to suppress microbial growth in drinking water distribution systems. In monochloraminated drinking water, a significant amount of extracellular DNA (eDNA) has been reported, which has many implications ranging from obscuring DNA-based drinking water microbiome analyses to posing potential health concerns. To address this, it is imperative for us to know the origin of the eDNA in drinking water. Using Pseudomonas aeruginosa as a model organism, we report for the first time that MCA induces the release of nucleic acids from both biofilms and planktonic cells. Upon exposure to 2 mg/L MCA, massive release of DNA from suspended cells in both MilliQ water and 0.9% NaCl was directly visualized using live cell imaging in a CellASIC ONIX2 microfluidic system. Exposing established biofilms to MCA also resulted in DNA release from the biofilms, which was confirmed by increased detection of eDNA in the effluent. Intriguingly, massive release of RNA was also observed, and the extracellular RNA (eRNA) was also found to persist in water for days. Sequencing analyses of the eDNA revealed that it could be used to assemble the whole genome of the model organism, while in the water, certain fragments of the genome were more persistent than others. RNA sequencing showed that the eRNA contains non-coding RNA and mRNA, implying its role as a possible signaling molecule in environmental systems and a snapshot of the past metabolic state of the bacterial cells.
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Affiliation(s)
- Sakcham Bairoliya
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore
| | - Apoorva Goel
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Manisha Mukherjee
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore
| | - Jonas Koh Zhi Xiang
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Bin Cao
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Program, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore
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Transcriptomic Analysis of Staphylococcus equorum KM1031, Isolated from the High-Salt Fermented Seafood Jeotgal, under Salt Stress. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8080403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Staphylococcus equorum is a potential starter for Korean high-salt fermented foods because of its salt tolerance and enzymatic activities that contribute to enhanced sensory properties of the food products. However, the mechanisms of salt tolerance of S. equorum are not fully understood. Here, RNA sequencing was performed on S. equorum strain KM1031 exposed to 7% NaCl (w/v) for 2 and 4 h to determine global gene expression changes. Salt pressure for 2 and 4 h resulted in significant differential expression of 4.8% (106/2209) and 6.1% (134/2209) of S. equorum KM1031 genes, respectively. Twenty-five core genes were differentially expressed on salt treatment for both 2 and 4 h, seven of which were related to osmoprotectant uptake and synthesis. We analyzed the genome of strain KM1031 and identified osmoprotectant uptake (Opu) systems, potassium importers, sodium exporters, and the glycine betaine synthesis system. The RNA sequencing results indicated that the OpuD system and glycine betaine synthesis might play the main roles in the salt tolerance of strain KM1031. Finally, the results of RNA sequencing were validated by quantitative real-time PCR of likely salt stress-related genes. This transcriptomic analysis provides evidence regarding the osmotic stress responses of S. equorum strain KM1031.
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Liu Y, Cai Y, Li G, Wang W, Wong PK, An T. Response mechanisms of different antibiotic-resistant bacteria with different resistance action targets to the stress from photocatalytic oxidation. WATER RESEARCH 2022; 218:118407. [PMID: 35453030 DOI: 10.1016/j.watres.2022.118407] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/18/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
The stress response of antibiotic-resistant bacteria (ARB) and the spread of antibiotic resistance genes (ARGs) pose a serious threat to the aquatic environment and human beings. This study mainly explored the effect of the heterogeneous photocatalytic oxidation (UVA-TiO2 system) on the stress response mechanism of ARB with different antibiotic resistance action targets, including the cell wall, proteins, DNA, RNA, folate and the cell membrane. Results indicate that the stress response mechanism of tetracycline- and sulfamethoxazole-resistant E. coli DH5α, which targets the synthesis of protein and folate, could rapidly induce global regulators by the overexpression of relative antibiotic resistance action target genes. Different stress response systems were mediated via cross-protection mechanism, causing stronger tolerance to an adverse environment than other ARB. Moreover, the photocatalytic inactivation mechanism of bacterial cells and a graded response of cellular stress mechanism caused differences in the intensity of the stress mechanism of antibiotic resistance action targets. E. coli DH5α resistant to cefotaxime and polymyxin, targeting synthesis of the cell wall and cell membrane, respectively, could confer greater advantages to bacterial survival and higher conjugative transfer frequency than E. coli DH5α resistant to nalidixic acid and rifampicin, which target the synthesis of DNA and RNA, respectively. This new perspective provides detailed information on the practical application of photocatalytic oxidation for inactivating ARB and hampering the spreading of ARGs in the aquatic environment.
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Affiliation(s)
- Yongjie Liu
- Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Yiwei Cai
- Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Guiying Li
- Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Wanjun Wang
- Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Po Keung Wong
- Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
| | - Taicheng An
- Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
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12
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Dubay MM, Johnston N, Wronkiewicz M, Lee J, Lindensmith CA, Nadeau JL. Quantification of Motility in Bacillus subtilis at Temperatures Up to 84°C Using a Submersible Volumetric Microscope and Automated Tracking. Front Microbiol 2022; 13:836808. [PMID: 35531296 PMCID: PMC9069135 DOI: 10.3389/fmicb.2022.836808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/10/2022] [Indexed: 11/13/2022] Open
Abstract
We describe a system for high-temperature investigations of bacterial motility using a digital holographic microscope completely submerged in heated water. Temperatures above 90°C could be achieved, with a constant 5°C offset between the sample temperature and the surrounding water bath. Using this system, we observed active motility in Bacillus subtilis up to 66°C. As temperatures rose, most cells became immobilized on the surface, but a fraction of cells remained highly motile at distances of >100 μm above the surface. Suspended non-motile cells showed Brownian motion that scaled consistently with temperature and viscosity. A novel open-source automated tracking package was used to obtain 2D tracks of motile cells and quantify motility parameters, showing that swimming speed increased with temperature until ∼40°C, then plateaued. These findings are consistent with the observed heterogeneity of B. subtilis populations, and represent the highest reported temperature for swimming in this species. This technique is a simple, low-cost method for quantifying motility at high temperatures and could be useful for investigation of many different cell types, including thermophilic archaea.
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Affiliation(s)
- Megan M. Dubay
- Department of Physics, Portland State University, Portland, OR, United States
| | - Nikki Johnston
- Department of Physics, Portland State University, Portland, OR, United States
| | - Mark Wronkiewicz
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | - Jake Lee
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | | | - Jay L. Nadeau
- Department of Physics, Portland State University, Portland, OR, United States
- *Correspondence: Jay L. Nadeau,
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13
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Zhang B, Xue K, Zhou S, Wang K, Liu W, Xu C, Cui L, Li L, Ran Q, Wang Z, Hu R, Hao Y, Cui X, Wang Y. Environmental selection overturns the decay relationship of soil prokaryotic community over geographic distance across grassland biotas. eLife 2022; 11:70164. [PMID: 35073255 PMCID: PMC8828049 DOI: 10.7554/elife.70164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 01/21/2022] [Indexed: 11/26/2022] Open
Abstract
Though being fundamental to global diversity distribution, little is known about the geographic pattern of soil microorganisms across different biotas on a large scale. Here, we investigated soil prokaryotic communities from Chinese northern grasslands on a scale up to 4000 km in both alpine and temperate biotas. Prokaryotic similarities increased over geographic distance after tipping points of 1760–1920 km, generating a significant U-shape pattern. Such pattern was likely due to decreased disparities in environmental heterogeneity over geographic distance when across biotas, supported by three lines of evidences: (1) prokaryotic similarities still decreased with the environmental distance, (2) environmental selection dominated prokaryotic assembly, and (3) short-term environmental heterogeneity followed the U-shape pattern spatially, especially attributed to dissolved nutrients. In sum, these results demonstrate that environmental selection overwhelmed the geographic ‘distance’ effect when across biotas, overturning the previously well-accepted geographic pattern for microbes on a large scale.
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Affiliation(s)
- Biao Zhang
- College of Resources and Environment, University of Chinese Academy of Sciences
| | - Kai Xue
- College of Resources and Environment, University of Chinese Academy of Sciences
| | - Shutong Zhou
- College of Life Sciences, University of Chinese Academy of Sciences
| | - Kui Wang
- College of Life Sciences, University of Chinese Academy of Sciences
| | - Wenjing Liu
- College of Resources and Environment, University of Chinese Academy of Sciences
| | - Cong Xu
- Aerospace Information Research Institute, University of Chinese Academy of Sciences
| | - Lizhen Cui
- College of Life Sciences, University of Chinese Academy of Sciences
| | - Linfeng Li
- College of Resources and Environment, University of Chinese Academy of Sciences
| | - Qinwei Ran
- College of Life Sciences, University of Chinese Academy of Sciences
| | - Zongsong Wang
- College of Life Sciences, University of Chinese Academy of Sciences
| | - Ronghai Hu
- College of Resources and Environment, University of Chinese Academy of Sciences
| | - Yanbin Hao
- College of Life Sciences, University of Chinese Academy of Sciences
| | - Xiaoyong Cui
- Key Laboratory of Adaptation and Evolution of Plateau Biota, University of Chinese Academy of Sciences
| | - Yanfen Wang
- College of Resources and Environment, University of Chinese Academy of Sciences
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14
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Rawat M, Srivastava A, Johri S, Gupta I, Karmodiya K. Single-Cell RNA Sequencing Reveals Cellular Heterogeneity and Stage Transition under Temperature Stress in Synchronized Plasmodium falciparum Cells. Microbiol Spectr 2021; 9:e0000821. [PMID: 34232098 PMCID: PMC8552519 DOI: 10.1128/spectrum.00008-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/26/2021] [Indexed: 12/12/2022] Open
Abstract
The malaria parasite has a complex life cycle exhibiting phenotypic and morphogenic variations in two different hosts by existing in heterogeneous developmental states. To investigate this cellular heterogeneity of the parasite within the human host, we performed single-cell RNA sequencing of synchronized Plasmodium cells under control and temperature treatment conditions. Using the Malaria Cell Atlas (https://www.sanger.ac.uk/science/tools/mca) as a guide, we identified 9 subtypes of the parasite distributed across known intraerythrocytic stages. Interestingly, temperature treatment results in the upregulation of the AP2-G gene, the master regulator of sexual development in a small subpopulation of the parasites. Moreover, we identified a heterogeneous stress-responsive subpopulation (clusters 5, 6, and 7 [∼10% of the total population]) that exhibits upregulation of stress response pathways under normal growth conditions. We also developed an online exploratory tool that will provide new insights into gene function under normal and temperature stress conditions. Thus, our study reveals important insights into cell-to-cell heterogeneity in the parasite population under temperature treatment that will be instrumental toward a mechanistic understanding of cellular adaptation and population dynamics in Plasmodium falciparum. IMPORTANCE The malaria parasite has a complex life cycle exhibiting phenotypic variations in two different hosts accompanied by cell-to-cell variability that is important for stress tolerance, immune evasion, and drug resistance. To investigate cellular heterogeneity determined by gene expression, we performed single-cell RNA sequencing (scRNA-seq) of about 12,000 synchronized Plasmodium cells under physiologically relevant normal (37°C) and temperature stress (40°C) conditions phenocopying the cyclic bouts of fever experienced during malarial infection. In this study, we found that parasites exhibit transcriptional heterogeneity in an otherwise morphologically synchronized culture. Also, a subset of parasites is continually committed to gametocytogenesis and stress-responsive pathways. These observations have important implications for understanding the mechanisms of drug resistance generation and vaccine development against the malaria parasite.
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Affiliation(s)
- Mukul Rawat
- Department of Biology, Indian Institute of Science Education and Research, Pashan, Pune, Maharashtra, India
| | - Ashish Srivastava
- Department of Biology, Indian Institute of Science Education and Research, Pashan, Pune, Maharashtra, India
| | - Shreya Johri
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - Ishaan Gupta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - Krishanpal Karmodiya
- Department of Biology, Indian Institute of Science Education and Research, Pashan, Pune, Maharashtra, India
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15
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Schwall CP, Loman TE, Martins BMC, Cortijo S, Villava C, Kusmartsev V, Livesey T, Saez T, Locke JCW. Tunable phenotypic variability through an autoregulatory alternative sigma factor circuit. Mol Syst Biol 2021; 17:e9832. [PMID: 34286912 PMCID: PMC8287880 DOI: 10.15252/msb.20209832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 11/17/2022] Open
Abstract
Genetically identical individuals in bacterial populations can display significant phenotypic variability. This variability can be functional, for example by allowing a fraction of stress prepared cells to survive an otherwise lethal stress. The optimal fraction of stress prepared cells depends on environmental conditions. However, how bacterial populations modulate their level of phenotypic variability remains unclear. Here we show that the alternative sigma factor σV circuit in Bacillus subtilis generates functional phenotypic variability that can be tuned by stress level, environmental history and genetic perturbations. Using single-cell time-lapse microscopy and microfluidics, we find the fraction of cells that immediately activate σV under lysozyme stress depends on stress level and on a transcriptional memory of previous stress. Iteration between model and experiment reveals that this tunability can be explained by the autoregulatory feedback structure of the sigV operon. As predicted by the model, genetic perturbations to the operon also modulate the response variability. The conserved sigma-anti-sigma autoregulation motif is thus a simple mechanism for bacterial populations to modulate their heterogeneity based on their environment.
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Affiliation(s)
| | | | - Bruno M C Martins
- Sainsbury LaboratoryUniversity of CambridgeCambridgeUK
- School of Life SciencesUniversity of WarwickCoventryUK
| | | | | | | | - Toby Livesey
- Sainsbury LaboratoryUniversity of CambridgeCambridgeUK
| | - Teresa Saez
- Sainsbury LaboratoryUniversity of CambridgeCambridgeUK
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16
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Murugan A, Husain K, Rust MJ, Hepler C, Bass J, Pietsch JMJ, Swain PS, Jena SG, Toettcher JE, Chakraborty AK, Sprenger KG, Mora T, Walczak AM, Rivoire O, Wang S, Wood KB, Skanata A, Kussell E, Ranganathan R, Shih HY, Goldenfeld N. Roadmap on biology in time varying environments. Phys Biol 2021; 18:10.1088/1478-3975/abde8d. [PMID: 33477124 PMCID: PMC8652373 DOI: 10.1088/1478-3975/abde8d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 01/21/2021] [Indexed: 02/02/2023]
Abstract
Biological organisms experience constantly changing environments, from sudden changes in physiology brought about by feeding, to the regular rising and setting of the Sun, to ecological changes over evolutionary timescales. Living organisms have evolved to thrive in this changing world but the general principles by which organisms shape and are shaped by time varying environments remain elusive. Our understanding is particularly poor in the intermediate regime with no separation of timescales, where the environment changes on the same timescale as the physiological or evolutionary response. Experiments to systematically characterize the response to dynamic environments are challenging since such environments are inherently high dimensional. This roadmap deals with the unique role played by time varying environments in biological phenomena across scales, from physiology to evolution, seeking to emphasize the commonalities and the challenges faced in this emerging area of research.
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Affiliation(s)
- Arvind Murugan
- James Franck Institute, Department of Physics, University of Chicago, Chicago, IL 60637, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Kabir Husain
- James Franck Institute, Department of Physics, University of Chicago, Chicago, IL 60637, United States of America
| | - Michael J Rust
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, United States of America,Department of Physics, University of Chicago, Chicago, IL 60637, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Chelsea Hepler
- Department of Medicine, Feinberg School of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Joseph Bass
- Department of Medicine, Feinberg School of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Julian M J Pietsch
- SynthSys: Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Peter S Swain
- SynthSys: Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Siddhartha G Jena
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States of America
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Arup K Chakraborty
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America,Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America,Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America,Ragon Institute of the Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard, Cambridge, MA 02139, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Kayla G Sprenger
- Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America,Ragon Institute of the Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard, Cambridge, MA 02139, United States of America
| | - T Mora
- Laboratoire de physique, Ecole normale supérieure, CNRS, PSL Research University, Paris, France
| | - A M Walczak
- Laboratoire de physique, Ecole normale supérieure, CNRS, PSL Research University, Paris, France
| | - O Rivoire
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Shenshen Wang
- Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Kevin B Wood
- Departments of Biophysics and Physics, University of Michigan, Ann Arbor, MI 48109-1055, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Antun Skanata
- Center for Genomics and Systems Biology, New York University, 12 Waverly Place, Rm. 206, New York, NY 10003, United States of America
| | - Edo Kussell
- Center for Genomics and Systems Biology, New York University, 12 Waverly Place, Rm. 206, New York, NY 10003, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Rama Ranganathan
- Center for Physics of Evolving Systems, Biochemistry & Molecular Biology, and the Pritzker School for Molecular Engineering, University of Chicago, Chicago IL 60637, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
| | - Hong-Yan Shih
- Department of Physics, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, United States of America,Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Nigel Goldenfeld
- Department of Physics, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, United States of America,Carl R Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, United States of America,Author to whom any correspondence should be addressed. , , , , , , , , , , and
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17
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Thiemicke A, Neuert G. Kinetics of osmotic stress regulate a cell fate switch of cell survival. SCIENCE ADVANCES 2021; 7:7/8/eabe1122. [PMID: 33608274 PMCID: PMC7895434 DOI: 10.1126/sciadv.abe1122] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 01/06/2021] [Indexed: 05/02/2023]
Abstract
Exposure of cells to diverse types of stressful environments differentially regulates cell fate. Although many types of stresses causing this differential regulation are known, it is unknown how changes over time of the same stressor regulate cell fate. Changes in extracellular osmolarity are critically involved in physiological and pathophysiological processes in several tissues. We observe that human cells survive gradual but not acute hyperosmotic stress. We find that stress, caspase, and apoptosis signaling do not activate during gradual stress in contrast to acute treatments. Contrary to the current paradigm, we see a substantial accumulation of proline in cells treated with gradual but not acute stresses. We show that proline can protect cells from hyperosmotic stress similar to the osmoprotection in plants and bacteria. Our studies found a cell fate switch that enables cells to survive gradually changing stress environments by preventing caspase activation and protect cells through proline accumulation.
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Affiliation(s)
- Alexander Thiemicke
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, USA
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Gregor Neuert
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, USA.
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, USA
- Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, TN, USA
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, USA
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18
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Meng D, Mukhitov N, Neitzey D, Lucht M, Schaak DD, Voigt CA. Rapid and simultaneous screening of pathway designs and chassis organisms, applied to engineered living materials. Metab Eng 2021; 66:308-318. [PMID: 33460821 DOI: 10.1016/j.ymben.2021.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/14/2020] [Accepted: 01/10/2021] [Indexed: 01/22/2023]
Abstract
Achieving a high product titer through pathway optimization often requires screening many combinations of enzymes and genetic parts. Typically, a library is screened in a single chassis that is a model or production organism. Here, we present a technique where the library is first introduced into B. subtilis XPORT, which has the ability to transfer the DNA to many Gram-positive species using an inducible integrated conjugated element (ICE). This approach is demonstrated using a two-gene pathway that converts tyrosine to melanin, a pigment biopolymer that can serve as a protective coating. A library of 18 pathway variants is conjugated by XPORT into 18 species, including those isolated from soil and industrial contaminants. The resulting 324 strains are screened and the highest titer is 1.2 g/L in B. amyloliquefaciens BT16. The strains were evaluated as co-cultures in an industrial process to make mycelia-grown bulk materials, where the bacteria need to be productive in a stressful, spatially non-uniform and dynamic environment. B. subtilis BGSC 3A35 is found to perform well under these conditions and make melanin in the material, which can be seen visually. This approach enables the simultaneous screening of genetic designs and chassis during the build step of metabolic engineering.
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Affiliation(s)
- Dechuan Meng
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Nikita Mukhitov
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Dana Neitzey
- Ecovative Design LLC, 70 Cohoes Avenue, Green Island, NY, 12183, USA
| | - Matthew Lucht
- Ecovative Design LLC, 70 Cohoes Avenue, Green Island, NY, 12183, USA
| | - Damen D Schaak
- Ecovative Design LLC, 70 Cohoes Avenue, Green Island, NY, 12183, USA
| | - Christopher A Voigt
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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19
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Johnson AN, Li G, Jashnsaz H, Thiemicke A, Kesler BK, Rogers DC, Neuert G. A rate threshold mechanism regulates MAPK stress signaling and survival. Proc Natl Acad Sci U S A 2021; 118:e2004998118. [PMID: 33443180 PMCID: PMC7812835 DOI: 10.1073/pnas.2004998118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cells are exposed to changes in extracellular stimulus concentration that vary as a function of rate. However, how cells integrate information conveyed from stimulation rate along with concentration remains poorly understood. Here, we examined how varying the rate of stress application alters budding yeast mitogen-activated protein kinase (MAPK) signaling and cell behavior at the single-cell level. We show that signaling depends on a rate threshold that operates in conjunction with stimulus concentration to determine the timing of MAPK signaling during rate-varying stimulus treatments. We also discovered that the stimulation rate threshold and stimulation rate-dependent cell survival are sensitive to changes in the expression levels of the Ptp2 phosphatase, but not of another phosphatase that similarly regulates osmostress signaling during switch-like treatments. Our results demonstrate that stimulation rate is a regulated determinant of cell behavior and provide a paradigm to guide the dissection of major stimulation rate dependent mechanisms in other systems.
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Affiliation(s)
- Amanda N Johnson
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Guoliang Li
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Hossein Jashnsaz
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Alexander Thiemicke
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Benjamin K Kesler
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Dustin C Rogers
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Gregor Neuert
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232;
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN 37232
- Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, TN 37232
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20
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Cambré A, Aertsen A. Bacterial Vivisection: How Fluorescence-Based Imaging Techniques Shed a Light on the Inner Workings of Bacteria. Microbiol Mol Biol Rev 2020; 84:e00008-20. [PMID: 33115939 PMCID: PMC7599038 DOI: 10.1128/mmbr.00008-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rise in fluorescence-based imaging techniques over the past 3 decades has improved the ability of researchers to scrutinize live cell biology at increased spatial and temporal resolution. In microbiology, these real-time vivisections structurally changed the view on the bacterial cell away from the "watery bag of enzymes" paradigm toward the perspective that these organisms are as complex as their eukaryotic counterparts. Capitalizing on the enormous potential of (time-lapse) fluorescence microscopy and the ever-extending pallet of corresponding probes, initial breakthroughs were made in unraveling the localization of proteins and monitoring real-time gene expression. However, later it became clear that the potential of this technique extends much further, paving the way for a focus-shift from observing single events within bacterial cells or populations to obtaining a more global picture at the intra- and intercellular level. In this review, we outline the current state of the art in fluorescence-based vivisection of bacteria and provide an overview of important case studies to exemplify how to use or combine different strategies to gain detailed information on the cell's physiology. The manuscript therefore consists of two separate (but interconnected) parts that can be read and consulted individually. The first part focuses on the fluorescent probe pallet and provides a perspective on modern methodologies for microscopy using these tools. The second section of the review takes the reader on a tour through the bacterial cell from cytoplasm to outer shell, describing strategies and methods to highlight architectural features and overall dynamics within cells.
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Affiliation(s)
- Alexander Cambré
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
| | - Abram Aertsen
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
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21
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Jashnsaz H, Fox ZR, Hughes JJ, Li G, Munsky B, Neuert G. Diverse Cell Stimulation Kinetics Identify Predictive Signal Transduction Models. iScience 2020; 23:101565. [PMID: 33083733 PMCID: PMC7549069 DOI: 10.1016/j.isci.2020.101565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 08/18/2020] [Accepted: 09/11/2020] [Indexed: 11/28/2022] Open
Abstract
Computationally understanding the molecular mechanisms that give rise to cell signaling responses upon different environmental, chemical, and genetic perturbations is a long-standing challenge that requires models that fit and predict quantitative responses for new biological conditions. Overcoming this challenge depends not only on good models and detailed experimental data but also on the rigorous integration of both. We propose a quantitative framework to perturb and model generic signaling networks using multiple and diverse changing environments (hereafter "kinetic stimulations") resulting in distinct pathway activation dynamics. We demonstrate that utilizing multiple diverse kinetic stimulations better constrains model parameters and enables predictions of signaling dynamics that would be impossible using traditional dose-response or individual kinetic stimulations. To demonstrate our approach, we use experimentally identified models to predict signaling dynamics in normal, mutated, and drug-treated conditions upon multitudes of kinetic stimulations and quantify which proteins and reaction rates are most sensitive to which extracellular stimulations.
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Affiliation(s)
- Hossein Jashnsaz
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - Zachary R. Fox
- Inria Saclay Ile-de-France, Palaiseau 91120, France
- Institut Pasteur, USR 3756 IP CNRS, Paris 75015, France
- Keck Scholars, School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Jason J. Hughes
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - Guoliang Li
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - Brian Munsky
- Keck Scholars, School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Gregor Neuert
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
- Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, TN 37232, USA
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
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22
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Theoretical study of the impact of adaptation on cell-fate heterogeneity and fractional killing. Sci Rep 2020; 10:17429. [PMID: 33060729 PMCID: PMC7562916 DOI: 10.1038/s41598-020-74238-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 09/22/2020] [Indexed: 02/07/2023] Open
Abstract
Fractional killing illustrates the cell propensity to display a heterogeneous fate response over a wide range of stimuli. The interplay between the nonlinear and stochastic dynamics of biochemical networks plays a fundamental role in shaping this probabilistic response and in reconciling requirements for heterogeneity and controllability of cell-fate decisions. The stress-induced fate choice between life and death depends on an early adaptation response which may contribute to fractional killing by amplifying small differences between cells. To test this hypothesis, we consider a stochastic modeling framework suited for comprehensive sensitivity analysis of dose response curve through the computation of a fractionality index. Combining bifurcation analysis and Langevin simulation, we show that adaptation dynamics enhances noise-induced cell-fate heterogeneity by shifting from a saddle-node to a saddle-collision transition scenario. The generality of this result is further assessed by a computational analysis of a detailed regulatory network model of apoptosis initiation and by a theoretical analysis of stochastic bifurcation mechanisms. Overall, the present study identifies a cooperative interplay between stochastic, adaptation and decision intracellular processes that could promote cell-fate heterogeneity in many contexts.
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23
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Bonilla CY. Generally Stressed Out Bacteria: Environmental Stress Response Mechanisms in Gram-Positive Bacteria. Integr Comp Biol 2020; 60:126-133. [PMID: 32044998 DOI: 10.1093/icb/icaa002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The ability to monitor the environment for toxic chemical and physical disturbances is essential for bacteria that live in dynamic environments. The fundamental sensing mechanisms and physiological responses that allow bacteria to thrive are conserved even if the molecular components of these pathways are not. The bacterial general stress response (GSR) represents a conceptual model for how one pathway integrates a wide range of environmental signals, and how a generalized system with broad molecular responses is coordinated to promote survival likely through complementary pathways. Environmental stress signals such as heat, osmotic stress, and pH changes are received by sensor proteins that through a signaling cascade activate the sigma factor, SigB, to regulate over 200 genes. Additionally, the GSR plays an important role in stress priming that increases bacterial fitness to unrelated subsequent stressors such as oxidative compounds. While the GSR response is implicated during oxidative stress, the reason for its activation remains unknown and suggests crosstalk between environmental and oxidative stress sensors and responses to coordinate antioxidant functions. Systems levels studies of cellular responses such as transcriptomes, proteomes, and metabolomes of stressed bacteria and single-cell analysis could shed light into the regulated functions that protect, remediate, and minimize damage during dynamic environments. This perspective will focus on fundamental stress sensing mechanisms and responses in Gram-positive bacterial species to illustrate their commonalities at the molecular and physiological levels; summarize exciting directions; and highlight how system-level approaches can help us understand bacterial physiology.
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Affiliation(s)
- Carla Y Bonilla
- Biology Department, Gonzaga University, 502 East Boone Avenue, Spokane, WA 99258, USA
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24
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Dixon G, Abbott E, Matz M. Meta-analysis of the coral environmental stress response: Acropora corals show opposing responses depending on stress intensity. Mol Ecol 2020; 29:2855-2870. [PMID: 32615003 DOI: 10.1111/mec.15535] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/25/2020] [Accepted: 06/18/2020] [Indexed: 12/15/2022]
Abstract
As climate change progresses, reef-building corals must contend more often with suboptimal conditions, motivating a need to understand coral stress response. Here, we test the hypothesis that there is a stereotyped transcriptional response that corals enact under all stressful conditions, functionally characterized by downregulation of growth, and activation of cell death, response to reactive oxygen species, immunity, and protein folding and degradation. We analyse RNA-seq and Tag-Seq data from 14 previously published studies and supplement them with four new experiments involving different stressors, totaling over 600 gene expression profiles from the genus Acropora. Contrary to expectations, we found not one, but two distinct types of response. The type A response was observed under all kinds of high-intensity stress, was correlated between independent projects and was functionally consistent with the hypothesized stereotyped response. The consistent correlation between projects, irrespective of stress type, supports the type A response as the general coral environmental stress response (ESR), a blanket solution to severely stressful conditions. The distinct type B response was observed under lower intensity stress and was more variable among studies. Unexpectedly, at the level of individual genes and functional categories, the type B response was broadly opposite the type A response. Finally, taking advantage of the breadth of the data set, we present contextual annotations for previously unannotated genes based on consistent stress-induced differences across independent projects.
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Affiliation(s)
- Groves Dixon
- Department of Integrative Biology, University of Texas, Austin, TX, USA
| | - Evelyn Abbott
- Department of Integrative Biology, University of Texas, Austin, TX, USA
| | - Mikhail Matz
- Department of Integrative Biology, University of Texas, Austin, TX, USA
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25
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Siller IG, Enders A, Gellermann P, Winkler S, Lavrentieva A, Scheper T, Bahnemann J. Characterization of a customized 3D-printed cell culture system using clear, translucent acrylate that enables optical online monitoring. Biomed Mater 2020; 15:055007. [DOI: 10.1088/1748-605x/ab8e97] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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26
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Guerreiro DN, Arcari T, O'Byrne CP. The σ B-Mediated General Stress Response of Listeria monocytogenes: Life and Death Decision Making in a Pathogen. Front Microbiol 2020; 11:1505. [PMID: 32733414 PMCID: PMC7358398 DOI: 10.3389/fmicb.2020.01505] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/10/2020] [Indexed: 12/17/2022] Open
Abstract
Sensing and responding to environmental cues is critical for the adaptability and success of the food-borne bacterial pathogen Listeria monocytogenes. A supramolecular multi-protein complex known as the stressosome, which acts as a stress sensing hub, is responsible for orchestrating the activation of a signal transduction pathway resulting in the activation of σB, the sigma factor that controls the general stress response (GSR). When σB is released from the anti-sigma factor RsbW, a rapid up-regulation of the large σB regulon, comprised of ≥ 300 genes, ensures that cells respond appropriately to the new environmental conditions. A diversity of stresses including low pH, high osmolarity, and blue light are known to be sensed by the stressosome, resulting in a generalized increase in stress resistance. Appropriate activation of the stressosome and deployment of σB are critical to fitness as there is a trade-off between growth and stress protection when the GSR is deployed. We review the recent developments in this field and describe an up-to-date model of how this sensory organelle might integrate environmental signals to produce an appropriate activation of the GSR. Some of the outstanding questions and challenges in this fascinating field are also discussed.
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Affiliation(s)
- Duarte N Guerreiro
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Talia Arcari
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
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27
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Rath H, Sappa PK, Hoffmann T, Gesell Salazar M, Reder A, Steil L, Hecker M, Bremer E, Mäder U, Völker U. Impact of high salinity and the compatible solute glycine betaine on gene expression of Bacillus subtilis. Environ Microbiol 2020; 22:3266-3286. [PMID: 32419322 DOI: 10.1111/1462-2920.15087] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/30/2020] [Accepted: 05/13/2020] [Indexed: 12/15/2022]
Abstract
The Gram-positive bacterium Bacillus subtilis is frequently exposed to hyperosmotic conditions. In addition to the induction of genes involved in the accumulation of compatible solutes, high salinity exerts widespread effects on B. subtilis physiology, including changes in cell wall metabolism, induction of an iron limitation response, reduced motility and suppression of sporulation. We performed a combined whole-transcriptome and proteome analysis of B. subtilis 168 cells continuously cultivated at low or high (1.2 M NaCl) salinity. Our study revealed significant changes in the expression of more than one-fourth of the protein-coding genes and of numerous non-coding RNAs. New aspects in understanding the impact of high salinity on B. subtilis include a sustained low-level induction of the SigB-dependent general stress response and strong repression of biofilm formation under high-salinity conditions. The accumulation of compatible solutes such as glycine betaine aids the cells to cope with water stress by maintaining physiologically adequate levels of turgor and also affects multiple cellular processes through interactions with cellular components. Therefore, we additionally analysed the global effects of glycine betaine on the transcriptome and proteome of B. subtilis and revealed that it influences gene expression not only under high-salinity, but also under standard growth conditions.
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Affiliation(s)
- Hermann Rath
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Praveen K Sappa
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Manuela Gesell Salazar
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Alexander Reder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Leif Steil
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Michael Hecker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology e.V. (IMaB), Greifswald, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology e.V. (IMaB), Greifswald, Germany
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28
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Rath H, Reder A, Hoffmann T, Hammer E, Seubert A, Bremer E, Völker U, Mäder U. Management of Osmoprotectant Uptake Hierarchy in Bacillus subtilis via a SigB-Dependent Antisense RNA. Front Microbiol 2020; 11:622. [PMID: 32373088 PMCID: PMC7186363 DOI: 10.3389/fmicb.2020.00622] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/19/2020] [Indexed: 01/20/2023] Open
Abstract
Under hyperosmotic conditions, bacteria accumulate compatible solutes through synthesis or import. Bacillus subtilis imports a large set of osmostress protectants via five osmotically controlled transport systems (OpuA to OpuE). Biosynthesis of the particularly effective osmoprotectant glycine betaine requires the exogenous supply of choline. While OpuB is rather specific for choline, OpuC imports a broad spectrum of compatible solutes, including choline and glycine betaine. One previously mapped antisense RNA of B. subtilis, S1290, exhibits strong and transient expression in response to a suddenly imposed salt stress. It covers the coding region of the opuB operon and is expressed from a strictly SigB-dependent promoter. By inactivation of this promoter and analysis of opuB and opuC transcript levels, we discovered a time-delayed osmotic induction of opuB that crucially depends on the S1290 antisense RNA and on the degree of the imposed osmotic stress. Time-delayed osmotic induction of opuB is apparently caused by transcriptional interference of RNA-polymerase complexes driving synthesis of the converging opuB and S1290 mRNAs. When our data are viewed in an ecophysiological framework, it appears that during the early adjustment phase of B. subtilis to acute osmotic stress, the cell prefers to initially rely on the transport activity of the promiscuous OpuC system and only subsequently fully induces opuB. Our data also reveal an integration of osmostress-specific adjustment systems with the SigB-controlled general stress response at a deeper level than previously appreciated.
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Affiliation(s)
- Hermann Rath
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Alexander Reder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Elke Hammer
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Andreas Seubert
- Faculty of Chemistry, Analytical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology e.V. (IMaB), Greifswald, Germany
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
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29
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Stochastic pulsing of gene expression enables the generation of spatial patterns in Bacillus subtilis biofilms. Nat Commun 2020; 11:950. [PMID: 32075967 PMCID: PMC7031267 DOI: 10.1038/s41467-020-14431-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/17/2019] [Indexed: 12/27/2022] Open
Abstract
Stochastic pulsing of gene expression can generate phenotypic diversity in a genetically identical population of cells, but it is unclear whether it has a role in the development of multicellular systems. Here, we show how stochastic pulsing of gene expression enables spatial patterns to form in a model multicellular system, Bacillus subtilis bacterial biofilms. We use quantitative microscopy and time-lapse imaging to observe pulses in the activity of the general stress response sigma factor σB in individual cells during biofilm development. Both σB and sporulation activity increase in a gradient, peaking at the top of the biofilm, even though σB represses sporulation. As predicted by a simple mathematical model, increasing σB expression shifts the peak of sporulation to the middle of the biofilm. Our results demonstrate how stochastic pulsing of gene expression can play a key role in pattern formation during biofilm development. Stochastic pulsing of gene expression can generate phenotypic diversity in a genetically identical population of cells. Here, the authors show that stochastic pulsing in the expression of a sigma factor enables the formation of spatial patterns in a multicellular system, Bacillus subtilis bacterial biofilms.
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30
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Microfluidic Single-Cell Analytics. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2020; 179:159-189. [PMID: 32737554 DOI: 10.1007/10_2020_134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
What is the impact of cellular heterogeneity on process performance? How do individual cells contribute to averaged process productivity? Single-cell analysis is a key technology for answering such key questions of biotechnology, beyond bulky measurements with populations. The analysis of cellular individuality, its origins, and the dependency of process performance on cellular heterogeneity has tremendous potential for optimizing biotechnological processes in terms of metabolic, reaction, and process engineering. Microfluidics offer unmatched environmental control of the cellular environment and allow massively parallelized cultivation of single cells. However, the analytical accessibility to a cell's physiology is of crucial importance for obtaining the desired information on the single-cell production phenotype. Highly sensitive analytics are required to detect and quantify the minute amounts of target analytes and small physiological changes in a single cell. For their application to biotechnological questions, single-cell analytics must evolve toward the measurement of kinetics and specific rates of the smallest catalytic unit, the single cell. In this chapter, we focus on an introduction to the latest single-cell analytics and their application for obtaining physiological parameters in a biotechnological context from single cells. We present and discuss recent advancements in single-cell analytics that enable the analysis of cell-specific growth, uptake, and production kinetics, as well as the gene expression and regulatory mechanisms at a single-cell level.
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31
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Castillo-Hair SM, Baerman EA, Fujita M, Igoshin OA, Tabor JJ. Optogenetic control of Bacillus subtilis gene expression. Nat Commun 2019; 10:3099. [PMID: 31308373 PMCID: PMC6629627 DOI: 10.1038/s41467-019-10906-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 06/07/2019] [Indexed: 01/27/2023] Open
Abstract
The Gram-positive bacterium Bacillus subtilis exhibits complex spatial and temporal gene expression signals. Although optogenetic tools are ideal for studying such processes, none has been engineered for this organism. Here, we port a cyanobacterial light sensor pathway comprising the green/red photoreversible two-component system CcaSR, two metabolic enzymes for production of the chromophore phycocyanobilin (PCB), and an output promoter to control transcription of a gene of interest into B. subtilis. Following an initial non-functional design, we optimize expression of pathway genes, enhance PCB production via a translational fusion of the biosynthetic enzymes, engineer a strong chimeric output promoter, and increase dynamic range with a miniaturized photosensor kinase. Our final design exhibits over 70-fold activation and rapid response dynamics, making it well-suited to studying a wide range of gene regulatory processes. In addition, the synthetic biology methods we develop to port this pathway should make B. subtilis easier to engineer in the future.
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Affiliation(s)
| | - Elliot A Baerman
- Department of Biosciences, Rice University, 6100 Main St., Houston, TX, 77005, USA
| | - Masaya Fujita
- Department of Biology and Biochemistry, University of Houston, 4800 Calhoun Rd., Houston, TX, 77004, USA
| | - Oleg A Igoshin
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX, 77005, USA
- Department of Biosciences, Rice University, 6100 Main St., Houston, TX, 77005, USA
- Center for Theoretical Biophysics, Rice University, 6100 Main St., Houston, TX, 77005, USA
| | - Jeffrey J Tabor
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX, 77005, USA.
- Department of Biosciences, Rice University, 6100 Main St., Houston, TX, 77005, USA.
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32
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Thiemicke A, Jashnsaz H, Li G, Neuert G. Generating kinetic environments to study dynamic cellular processes in single cells. Sci Rep 2019; 9:10129. [PMID: 31300695 PMCID: PMC6625993 DOI: 10.1038/s41598-019-46438-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/27/2019] [Indexed: 01/28/2023] Open
Abstract
Cells of any organism are consistently exposed to changes over time in their environment. The kinetics by which these changes occur are critical for the cellular response and fate decision. It is therefore important to control the temporal changes of extracellular stimuli precisely to understand biological mechanisms in a quantitative manner. Most current cell culture and biochemical studies focus on instant changes in the environment and therefore neglect the importance of kinetic environments. To address these shortcomings, we developed two experimental methodologies to precisely control the environment of single cells. These methodologies are compatible with standard biochemistry, molecular, cell and quantitative biology assays. We demonstrate applicability by obtaining time series and time point measurements in both live and fixed cells. We demonstrate the feasibility of the methodology in yeast and mammalian cell culture in combination with widely used assays such as flow cytometry, time-lapse microscopy and single-molecule RNA Fluorescent in-situ Hybridization (smFISH). Our experimental methodologies are easy to implement in most laboratory settings and allows the study of kinetic environments in a wide range of assays and different cell culture conditions.
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Affiliation(s)
- Alexander Thiemicke
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, 37232, USA
| | - Hossein Jashnsaz
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, 37232, USA
| | - Guoliang Li
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, 37232, USA
| | - Gregor Neuert
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, 37232, USA. .,Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, TN, 37232, USA. .,Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, 37232, USA.
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33
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Abstract
A handful of core intercellular signaling pathways play pivotal roles in a broad variety of developmental processes. It has remained puzzling how so few pathways can provide the precision and specificity of cell-cell communication required for multicellular development. Solving this requires us to quantitatively understand how developmentally relevant signaling information is actively sensed, transformed and spatially distributed by signaling pathways. Recently, single cell analysis and cell-based reconstitution, among other approaches, have begun to reveal the 'communication codes' through which information is represented in the identities, concentrations, combinations and dynamics of extracellular ligands. They have also revealed how signaling pathways decipher these features and control the spatial distribution of signaling in multicellular contexts. Here, we review recent work reporting the discovery and analysis of communication codes and discuss their implications for diverse developmental processes.
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Affiliation(s)
- Pulin Li
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, Pasadena, CA 91125, USA
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34
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Labavić D, Ladjimi MT, Thommen Q, Pfeuty B. Scaling laws of cell-fate responses to transient stress. J Theor Biol 2019; 478:14-25. [PMID: 31202789 DOI: 10.1016/j.jtbi.2019.06.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 06/05/2019] [Accepted: 06/13/2019] [Indexed: 10/26/2022]
Abstract
Analysis and modelling of dose-survival curves of cells and tissues are often used to assess therapeutic efficacy or environmental risks, much less to infer the intracellular regulatory mechanisms of cellular stress response. However, systematic measurements of how cell survival depends on the time profile of stress, such as exposure duration, provide practical means to decipher the homeostatic dynamics of stress-response regulatory networks. In this paper, we propose a dynamical framework to theoretically address the relationship between cell fate response to a transient stress and the underlying regulatory feedback mechanisms. A simple network topology that couples a homeostatic negative feedback and a death-triggering positive feedback is shown to display four response regimes for which the iso-effect relationships between duration and intensity are captured by specific power laws. These distinct response regimes define several windows of stress duration for which lethality is not merely proportional to the product of intensity and duration, and, thus, for which cells are either more tolerant or more vulnerable to a given dose. Overall, this study highlights the differential roles of feedback strength, timescale and nonlinearity in promoting survivability to particular stress profiles, providing a valuable framework for a comparative analysis of diverse stress-specific regulatory networks.
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Affiliation(s)
- Darka Labavić
- Univ. Lille CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France.
| | - Mohamed Tahar Ladjimi
- Univ. Lille CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Quentin Thommen
- Univ. Lille CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Benjamin Pfeuty
- Univ. Lille CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France.
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35
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Ballesteros-Garrido R, Montagud-Martínez R, Rodrigo G. Bacterial Population Control with Macroscopic HKUST Crystals. ACS APPLIED MATERIALS & INTERFACES 2019; 11:19878-19883. [PMID: 31090390 DOI: 10.1021/acsami.9b05285] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Macroscopic HKUST crystals were shown to release significant amounts of copper in saline medium at a slow rate, which was exploited to control the growth of a bacterial population. This was achieved in both liquid and solid media, the latter illustrating the local effect of the crystals. In addition, these nanostructured crystals of observable size were loaded with chloramphenicol to exert a joint metal-antibiotic action, going beyond the traditional oligodynamic effect.
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Affiliation(s)
- Rafael Ballesteros-Garrido
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-U. Valencia , 9 Cat. Agustin Escardino , 46980 Paterna , Spain
| | - Roser Montagud-Martínez
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-U. Valencia , 9 Cat. Agustin Escardino , 46980 Paterna , Spain
| | - Guillermo Rodrigo
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-U. Valencia , 9 Cat. Agustin Escardino , 46980 Paterna , Spain
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36
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Heemskerk I, Burt K, Miller M, Chhabra S, Guerra MC, Liu L, Warmflash A. Rapid changes in morphogen concentration control self-organized patterning in human embryonic stem cells. eLife 2019; 8:e40526. [PMID: 30829572 PMCID: PMC6398983 DOI: 10.7554/elife.40526] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/14/2019] [Indexed: 12/31/2022] Open
Abstract
During embryonic development, diffusible signaling molecules called morphogens are thought to determine cell fates in a concentration-dependent way. Yet, in mammalian embryos, concentrations change rapidly compared to the time for making cell fate decisions. Here, we use human embryonic stem cells (hESCs) to address how changing morphogen levels influence differentiation, focusing on how BMP4 and Nodal signaling govern the cell-fate decisions associated with gastrulation. We show that BMP4 response is concentration dependent, but that expression of many Nodal targets depends on rate of concentration change. Moreover, in a self-organized stem cell model for human gastrulation, expression of these genes follows rapid changes in endogenous Nodal signaling. Our study shows a striking contrast between the specific ways ligand dynamics are interpreted by two closely related signaling pathways, highlighting both the subtlety and importance of morphogen dynamics for understanding mammalian embryogenesis and designing optimized protocols for directed stem cell differentiation. Editorial note This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Idse Heemskerk
- Department of BiosciencesRice UniversityHoustonUnited States
| | - Kari Burt
- Department of BiosciencesRice UniversityHoustonUnited States
| | - Matthew Miller
- Department of BiosciencesRice UniversityHoustonUnited States
| | - Sapna Chhabra
- Systems, Synthetic and Physical Biology ProgramRice UniversityHoustonUnited States
| | | | - Lizhong Liu
- Department of BiosciencesRice UniversityHoustonUnited States
| | - Aryeh Warmflash
- Department of BiosciencesRice UniversityHoustonUnited States
- Department of BioengineeringRice UniversityHoustonUnited States
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37
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Lugagne JB, Dunlop MJ. Cell-machine interfaces for characterizing gene regulatory network dynamics. ACTA ACUST UNITED AC 2019; 14:1-8. [PMID: 31579842 DOI: 10.1016/j.coisb.2019.01.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Gene regulatory networks and the dynamic responses they produce offer a wealth of information about how biological systems process information about their environment. Recently, researchers interested in dissecting these networks have been outsourcing various parts of their experimental workflow to computers. Here we review how, using microfluidic or optogenetic tools coupled with fluorescence imaging, it is now possible to interface cells and computers. These platforms enable scientists to perform informative dynamic stimulations of genetic pathways and monitor their reaction. It is also possible to close the loop and regulate genes in real time, providing an unprecedented view of how signals propagate through the network. Finally, we outline new tools that can be used within the framework of cell-machine interfaces.
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Affiliation(s)
- Jean-Baptiste Lugagne
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.,Biological Design Center, Boston University, Boston, MA, USA
| | - Mary J Dunlop
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.,Biological Design Center, Boston University, Boston, MA, USA
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38
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Role and regulation of the stress activated sigma factor sigma B (σ B) in the saprophytic and host-associated life stages of Listeria monocytogenes. ADVANCES IN APPLIED MICROBIOLOGY 2019; 106:1-48. [PMID: 30798801 DOI: 10.1016/bs.aambs.2018.11.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The stress activated sigma factor sigma B (σB) plays a pivotal role in allowing the food-borne bacterial pathogen Listeria monocytogenes to modulate its transcriptional landscape in order to survive in a variety of harsh environments both outside and within the host. While we have a comparatively good understanding of the systems under the control of this sigma factor much less is known about how the activity of σB is controlled. In this review, we present a current model describing how this sigma factor is thought to be controlled including an overview of what is known about stress sensing and the early signal transduction events that trigger its activation. We discuss the known regulatory overlaps between σB and other protein and RNA regulators in the cell. Finally, we describe the role of σB in surviving both saprophytic and host-associated stresses. The complexity of the regulation of this sigma factor reflects the significant role that it plays in the persistence of this important pathogen in the natural environment, the food chain as well as within the host during the early stages of an infection. Understanding its regulation will be a critical step in helping to develop rational strategies to prevent its growth and survival in the food destined for human consumption and in the prevention of listeriosis.
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39
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Haddad N, Johnson N, Kathariou S, Métris A, Phister T, Pielaat A, Tassou C, Wells-Bennik MH, Zwietering MH. Next generation microbiological risk assessment—Potential of omics data for hazard characterisation. Int J Food Microbiol 2018; 287:28-39. [DOI: 10.1016/j.ijfoodmicro.2018.04.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 03/31/2018] [Accepted: 04/10/2018] [Indexed: 12/18/2022]
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40
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Zacchetti B, Wösten HA, Claessen D. Multiscale heterogeneity in filamentous microbes. Biotechnol Adv 2018; 36:2138-2149. [DOI: 10.1016/j.biotechadv.2018.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 09/15/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022]
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Liu Z, Zhang J, Jin J, Geng Z, Qi Q, Liang Q. Programming Bacteria With Light-Sensors and Applications in Synthetic Biology. Front Microbiol 2018; 9:2692. [PMID: 30467500 PMCID: PMC6236058 DOI: 10.3389/fmicb.2018.02692] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 10/22/2018] [Indexed: 12/11/2022] Open
Abstract
Photo-receptors are widely present in both prokaryotic and eukaryotic cells, which serves as the foundation of tuning cell behaviors with light. While practices in eukaryotic cells have been relatively established, trials in bacterial cells have only been emerging in the past few years. A number of light sensors have been engineered in bacteria cells and most of them fall into the categories of two-component and one-component systems. Such a sensor toolbox has enabled practices in controlling synthetic circuits at the level of transcription and protein activity which is a major topic in synthetic biology, according to the central dogma. Additionally, engineered light sensors and practices of tuning synthetic circuits have served as a foundation for achieving light based real-time feedback control. Here, we review programming bacteria cells with light, introducing engineered light sensors in bacteria and their applications, including tuning synthetic circuits and achieving feedback controls over microbial cell culture.
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Affiliation(s)
- Zedao Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | - Jizhong Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | - Jiao Jin
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | - Zilong Geng
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | - Quanfeng Liang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
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42
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Passaris I, Cambré A, Govers SK, Aertsen A. Bimodal Expression of the Salmonella Typhimurium spv Operon. Genetics 2018; 210:621-635. [PMID: 30143595 PMCID: PMC6216589 DOI: 10.1534/genetics.118.300822] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 08/14/2018] [Indexed: 02/03/2023] Open
Abstract
The well-studied spv operon of Salmonellatyphimurium is important for causing full virulence in mice and both the regulation and function of the Spv proteins have been characterized extensively over the past several decades. Using quantitative single-cell fluorescence microscopy, we demonstrate the spv regulon to display a bimodal expression pattern that originates in the bimodal expression of the SpvR activator. The spv expression pattern is influenced by growth conditions and the specific Styphimurium strain used, but does not require Salmonella-specific virulence regulators. By monitoring real-time promoter kinetics, we reveal that SpvA has the ability to impart negative feedback on spvABCD expression without affecting spvR expression. Together, our data suggest that the SpvA protein counteracts the positive feedback loop imposed by SpvR, and could thus be responsible for dampening spvABCD expression and coordinating virulence protein production in time. The results presented here yield new insights in the intriguing regulation of the spv operon and adds this operon to the growing list of virulence factors exhibiting marked expression heterogeneity in Styphimurium.
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Affiliation(s)
- Ioannis Passaris
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Alexander Cambré
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Sander K Govers
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Abram Aertsen
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
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43
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Nené NR, Rivington J, Zaikin A. Sensitivity of asymmetric rate-dependent critical systems to initial conditions: Insights into cellular decision making. Phys Rev E 2018; 98:022317. [PMID: 30253525 DOI: 10.1103/physreve.98.022317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Indexed: 11/07/2022]
Abstract
The work reported here aims to address the effects of time-dependent parameters and stochasticity on decision making in biological systems. We achieve this by extending previous studies that resorted to simple bifurcation normal forms, although in the present case we focus primarily on the issue of the system's sensitivity to initial conditions in the presence of two different noise distributions, Gaussian and Lévy. In addition, we also assess the impact of two-way sweeping at different rates through the critical region of a canonical Pitchfork bifurcation with a constant external asymmetry. The parallel with decision making in biocircuits is performed on this simple system since it is equivalent in its available states and dynamics to more complex genetic circuits published previously. Overall we verify that rate-dependent effects, previously reported as being important features of bifurcating systems, are specific to particular initial conditions. Processing of each starting state, which for the normal form underlying this study is akin to a classification task, is affected by the balance between sweeping speed through critical regions and the type of fluctuations added. For the heavy-tailed noise, two-way dynamic bifurcations are more efficient in processing the external signals, here understood to be jointly represented by the critical parameter profile and the external asymmetry amplitude, when compared to the system relying on escape dynamics. This is particular to the case when the system starts at an attractor not favored by the asymmetry and, in conjunction, when the sweeping amplitude is large.
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Affiliation(s)
- Nuno R Nené
- Department of Genetics, University of Cambridge, CB2 3EH Cambridge, United Kingdom.,Institute for Women's Health, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - James Rivington
- Department of Mathematics, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - Alexey Zaikin
- Institute for Women's Health, University College London, Gower Street, WC1E 6BT London, United Kingdom.,Department of Mathematics, University College London, Gower Street, WC1E 6BT London, United Kingdom.,Department of Applied Mathematics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
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44
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Controllable stress patterns over multi-generation timescale in microfluidic devices. Methods Cell Biol 2018. [PMID: 30165960 DOI: 10.1016/bs.mcb.2018.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The generation of complex temporal stress patterns may be instrumental to investigate the adaptive properties of individual cells submitted to environmental stress on physiological timescale. However, it is difficult to accurately control stress concentration over time in bulk experiments. Here, we describe a microfluidics-based protocol to induce tightly controllable H2O2 stress in budding yeast while constantly monitoring cell growth with single cell resolution over multi-generation timescale. Moreover, we describe a simple methodology to produce ramping H2O2 stress to investigate the homeostatic properties of the H2O2 scavenging system.
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45
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Chatterjee M, Acar M. Heritable stress response dynamics revealed by single-cell genealogy. SCIENCE ADVANCES 2018; 4:e1701775. [PMID: 29675464 PMCID: PMC5906080 DOI: 10.1126/sciadv.1701775] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 03/07/2018] [Indexed: 06/08/2023]
Abstract
Cells often respond to environmental stimuli by activating specific transcription factors. Upon exposure to glucose limitation stress, it is known that yeast Saccharomyces cerevisiae cells dephosphorylate the general stress response factor Msn2, leading to its nuclear localization, which in turn activates the expression of many genes. However, the precise dynamics of Msn2 nucleocytoplasmic translocations and whether they are inherited over multiple generations in a stress-dependent manner are not well understood. Tracking Msn2 localization events in yeast lineages grown on a microfluidic chip, here we report how cells modulate the amplitude, duration, frequency, and dynamic pattern of the localization events in response to glucose limitation stress. Single yeast cells were found to modulate the amplitude and frequency of Msn2 nuclear localization, but not its duration. Moreover, the Msn2 localization frequency was epigenetically inherited in descendants of mother cells, leading to a decrease in cell-to-cell variation in localization frequency. An analysis of the time dynamic patterns of nuclear localizations between genealogically related cell pairs using an information theory approach found that the magnitude of pattern similarity increased with stress intensity and was strongly inherited by the descendant cells at the highest stress level. By dissecting how general stress response dynamics is contributed by different modulation schemes over long time scales, our work provides insight into which scheme evolution might have acted on to optimize fitness in stressful environments.
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Affiliation(s)
- Meenakshi Chatterjee
- Department of Electrical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT 06520, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
| | - Murat Acar
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA
- Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, 300 George Street, Suite 501, New Haven, CT 06511, USA
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA
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46
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Heins AL, Weuster-Botz D. Population heterogeneity in microbial bioprocesses: origin, analysis, mechanisms, and future perspectives. Bioprocess Biosyst Eng 2018. [PMID: 29541890 DOI: 10.1007/s00449-018-1922-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Population heterogeneity is omnipresent in all bioprocesses even in homogenous environments. Its origin, however, is only so well understood that potential strategies like bet-hedging, noise in gene expression and division of labour that lead to population heterogeneity can be derived from experimental studies simulating the dynamics in industrial scale bioprocesses. This review aims at summarizing the current state of the different parts of single cell studies in bioprocesses. This includes setups to visualize different phenotypes of single cells, computational approaches connecting single cell physiology with environmental influence and special cultivation setups like scale-down reactors that have been proven to be useful to simulate large-scale conditions. A step in between investigation of populations and single cells is studying subpopulations with distinct properties that differ from the rest of the population with sub-omics methods which are also presented here. Moreover, the current knowledge about population heterogeneity in bioprocesses is summarized for relevant industrial production hosts and mixed cultures, as they provide the unique opportunity to distribute metabolic burden and optimize production processes in a way that is impossible in traditional monocultures. In the end, approaches to explain the underlying mechanism of population heterogeneity and the evidences found to support each hypothesis are presented. For instance, population heterogeneity serving as a bet-hedging strategy that is used as coordinated action against bioprocess-related stresses while at the same time spreading the risk between individual cells as it ensures the survival of least a part of the population in any environment the cells encounter.
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Affiliation(s)
- Anna-Lena Heins
- Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany.
| | - Dirk Weuster-Botz
- Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany
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47
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Park J, Dies M, Lin Y, Hormoz S, Smith-Unna SE, Quinodoz S, Hernández-Jiménez MJ, Garcia-Ojalvo J, Locke JCW, Elowitz MB. Molecular Time Sharing through Dynamic Pulsing in Single Cells. Cell Syst 2018; 6:216-229.e15. [PMID: 29454936 PMCID: PMC6070344 DOI: 10.1016/j.cels.2018.01.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 09/04/2017] [Accepted: 01/10/2018] [Indexed: 11/19/2022]
Abstract
In cells, specific regulators often compete for limited amounts of a core enzymatic resource. It is typically assumed that competition leads to partitioning of core enzyme molecules among regulators at constant levels. Alternatively, however, different regulatory species could time share, or take turns utilizing, the core resource. Using quantitative time-lapse microscopy, we analyzed sigma factor activity dynamics, and their competition for RNA polymerase, in individual Bacillus subtilis cells under energy stress. Multiple alternative sigma factors were activated in ~1-hr pulses in stochastic and repetitive fashion. Pairwise analysis revealed that two sigma factors rarely pulse simultaneously and that some pairs are anti-correlated, indicating that RNAP utilization alternates among different sigma factors. Mathematical modeling revealed how stochastic time-sharing dynamics can emerge from pulse-generating sigma factor regulatory circuits actively competing for RNAP. Time sharing provides a mechanism for cells to dynamically control the distribution of cell states within a population. Since core molecular components are limiting in many other systems, time sharing may represent a general mode of regulation.
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Affiliation(s)
- Jin Park
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marta Dies
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona Biomedical Research Park, 08003 Barcelona, Spain; Department of Physics and Nuclear Engineering, Universitat Politecnica de Catalunya, 08222 Terrassa, Spain; Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Yihan Lin
- Center for Quantitative Biology, and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Sahand Hormoz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | | | - Sofia Quinodoz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | | | - Jordi Garcia-Ojalvo
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona Biomedical Research Park, 08003 Barcelona, Spain.
| | - James C W Locke
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK; Microsoft Research, Cambridge, UK.
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA.
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48
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Eich C, Arlt J, Vink CS, Solaimani Kartalaei P, Kaimakis P, Mariani SA, van der Linden R, van Cappellen WA, Dzierzak E. In vivo single cell analysis reveals Gata2 dynamics in cells transitioning to hematopoietic fate. J Exp Med 2017; 215:233-248. [PMID: 29217535 PMCID: PMC5748852 DOI: 10.1084/jem.20170807] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 09/12/2017] [Accepted: 10/31/2017] [Indexed: 01/07/2023] Open
Abstract
Eich et al. reveal the dynamic expression of the Gata2 transcription factor in single aortic cells transitioning to hematopoietic fate by vital imaging of Gata2Venus mouse embryos. Pulsatile expression level changes highlight an unstable genetic state during hematopoietic cell generation. Cell fate is established through coordinated gene expression programs in individual cells. Regulatory networks that include the Gata2 transcription factor play central roles in hematopoietic fate establishment. Although Gata2 is essential to the embryonic development and function of hematopoietic stem cells that form the adult hierarchy, little is known about the in vivo expression dynamics of Gata2 in single cells. Here, we examine Gata2 expression in single aortic cells as they establish hematopoietic fate in Gata2Venus mouse embryos. Time-lapse imaging reveals rapid pulsatile level changes in Gata2 reporter expression in cells undergoing endothelial-to-hematopoietic transition. Moreover, Gata2 reporter pulsatile expression is dramatically altered in Gata2+/− aortic cells, which undergo fewer transitions and are reduced in hematopoietic potential. Our novel finding of dynamic pulsatile expression of Gata2 suggests a highly unstable genetic state in single cells concomitant with their transition to hematopoietic fate. This reinforces the notion that threshold levels of Gata2 influence fate establishment and has implications for transcription factor–related hematologic dysfunctions.
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Affiliation(s)
- Christina Eich
- Department of Cell Biology, Erasmus Stem Cell Institute, Erasmus Medical Center, Rotterdam, Netherlands
| | - Jochen Arlt
- School of Physics and Astronomy, The University of Edinburgh, Edinburgh, Scotland, UK
| | - Chris S Vink
- Centre for Inflammation Research, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, Scotland, UK
| | | | - Polynikis Kaimakis
- Department of Cell Biology, Erasmus Stem Cell Institute, Erasmus Medical Center, Rotterdam, Netherlands
| | - Samanta A Mariani
- Centre for Inflammation Research, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, Scotland, UK
| | - Reinier van der Linden
- Department of Cell Biology, Erasmus Stem Cell Institute, Erasmus Medical Center, Rotterdam, Netherlands
| | - Wiggert A van Cappellen
- Department of Pathology, Erasmus Optical Imaging Centre, Erasmus Medical Center, Rotterdam, Netherlands
| | - Elaine Dzierzak
- Department of Cell Biology, Erasmus Stem Cell Institute, Erasmus Medical Center, Rotterdam, Netherlands .,Centre for Inflammation Research, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, Scotland, UK
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49
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Stress Introduction Rate Alters the Benefit of AcrAB-TolC Efflux Pumps. J Bacteriol 2017; 200:JB.00525-17. [PMID: 29038251 DOI: 10.1128/jb.00525-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/05/2017] [Indexed: 11/20/2022] Open
Abstract
Stress tolerance studies are typically conducted in an all-or-none fashion. However, in realistic settings-such as in clinical or metabolic engineering applications-cells may encounter stresses at different rates. Therefore, how cells tolerate stress may depend on its rate of appearance. To address this, we studied how the rate of stress introduction affects bacterial stress tolerance by focusing on a key stress response mechanism. Efflux pumps, such as AcrAB-TolC of Escherichia coli, are membrane transporters well known for the ability to export a wide variety of substrates, including antibiotics, signaling molecules, and biofuels. Although efflux pumps improve stress tolerance, pump overexpression can result in a substantial fitness cost to the cells. We hypothesized that the ideal pump expression level would involve a rate-dependent trade-off between the benefit of pumps and the cost of their expression. To test this, we evaluated the benefit of the AcrAB-TolC pump under different rates of stress introduction, including a step, a fast ramp, and a gradual ramp. Using two chemically diverse stresses, the antibiotic chloramphenicol and the jet biofuel precursor pinene, we assessed the benefit provided by the pumps. A mathematical model describing these effects predicted the benefit as a function of the rate of stress introduction. Our findings demonstrate that as the rate of introduction is lowered, stress response mechanisms provide a disproportionate benefit to pump-containing strains, allowing cells to survive beyond the original inhibitory concentrations.IMPORTANCE Efflux pumps are ubiquitous in nature and provide stress tolerance in the cells of species ranging from bacteria to mammals. Understanding how pumps provide tolerance has far-reaching implications for diverse fields, from medicine to biotechnology. Here, we investigated how the rate of stressor appearance impacts tolerance. We focused on two distinct substrates of AcrAB-TolC efflux pumps, the antibiotic chloramphenicol and the biofuel precursor pinene. Interestingly, tolerance is highly dependent on the rate of stress introduction. Therefore, it is important to consider not only the total quantity of a stressor but also the rate at which it is applied. The implications of this work are significant because environments are rarely static; antibiotic concentrations change during dosing, and metabolic engineering processes change with time.
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50
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Rosenthal K, Oehling V, Dusny C, Schmid A. Beyond the bulk: disclosing the life of single microbial cells. FEMS Microbiol Rev 2017; 41:751-780. [PMID: 29029257 PMCID: PMC5812503 DOI: 10.1093/femsre/fux044] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 09/08/2017] [Indexed: 01/08/2023] Open
Abstract
Microbial single cell analysis has led to discoveries that are beyond what can be resolved with population-based studies. It provides a pristine view of the mechanisms that organize cellular physiology, unbiased by population heterogeneity or uncontrollable environmental impacts. A holistic description of cellular functions at the single cell level requires analytical concepts beyond the miniaturization of existing technologies, defined but uncontrolled by the biological system itself. This review provides an overview of the latest advances in single cell technologies and demonstrates their potential. Opportunities and limitations of single cell microbiology are discussed using selected application-related examples.
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Affiliation(s)
- Katrin Rosenthal
- Department Solar Materials, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
| | - Verena Oehling
- Department Solar Materials, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
| | - Christian Dusny
- Department Solar Materials, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
| | - Andreas Schmid
- Department Solar Materials, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
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