--- _id: '1571' abstract: - lang: eng text: Epistatic interactions can frustrate and shape evolutionary change. Indeed, phenotypes may fail to evolve when essential mutations are only accessible through positive selection if they are fixed simultaneously. How environmental variability affects such constraints is poorly understood. Here, we studied genetic constraints in fixed and fluctuating environments using the Escherichia coli lac operon as a model system for genotype-environment interactions. We found that, in different fixed environments, all trajectories that were reconstructed by applying point mutations within the transcription factor-operator interface became trapped at suboptima, where no additional improvements were possible. Paradoxically, repeated switching between these same environments allows unconstrained adaptation by continuous improvements. This evolutionary mode is explained by pervasive cross-environmental tradeoffs that reposition the peaks in such a way that trapped genotypes can repeatedly climb ascending slopes and hence, escape adaptive stasis. Using a Markov approach, we developed a mathematical framework to quantify the landscape-crossing rates and show that this ratchet-like adaptive mechanism is robust in a wide spectrum of fluctuating environments. Overall, this study shows that genetic constraints can be overcome by environmental change and that crossenvironmental tradeoffs do not necessarily impede but also, can facilitate adaptive evolution. Because tradeoffs and environmental variability are ubiquitous in nature, we speculate this evolutionary mode to be of general relevance. acknowledgement: This work is part of the research program of the Foundation for Fundamental Research on Matter, which is part of the Netherlands Organization for Scientific Research (NWO). M.G.J.d.V. was (partially) funded by NWO Earth and Life Sciences (ALW), project 863.14.015. We thank D. M. Weinreich, J. A. G. M. de Visser, T. Paixão, J. Polechová, T. Friedlander, and A. E. Mayo for reading and commenting on earlier versions of the manuscript and B. Houchmandzadeh, O. Rivoire, and M. Hemery for discussions and suggestions on the Markov computation. Furthermore, we thank F. J. Poelwijk for sharing plasmid pCascade5 and pRD007 and Y. Yokobayashi for sharing plasmid pINV-110. We also thank the anonymous reviewers for remarks on the initial version of the manuscript. author: - first_name: Marjon full_name: De Vos, Marjon id: 3111FFAC-F248-11E8-B48F-1D18A9856A87 last_name: De Vos - first_name: Alexandre full_name: Dawid, Alexandre last_name: Dawid - first_name: Vanda full_name: Šunderlíková, Vanda last_name: Šunderlíková - first_name: Sander full_name: Tans, Sander last_name: Tans citation: ama: de Vos M, Dawid A, Šunderlíková V, Tans S. Breaking evolutionary constraint with a tradeoff ratchet. PNAS. 2015;112(48):14906-14911. doi:10.1073/pnas.1510282112 apa: de Vos, M., Dawid, A., Šunderlíková, V., & Tans, S. (2015). Breaking evolutionary constraint with a tradeoff ratchet. PNAS. National Academy of Sciences. https://doi.org/10.1073/pnas.1510282112 chicago: Vos, Marjon de, Alexandre Dawid, Vanda Šunderlíková, and Sander Tans. “Breaking Evolutionary Constraint with a Tradeoff Ratchet.” PNAS. National Academy of Sciences, 2015. https://doi.org/10.1073/pnas.1510282112. ieee: M. de Vos, A. Dawid, V. Šunderlíková, and S. Tans, “Breaking evolutionary constraint with a tradeoff ratchet,” PNAS, vol. 112, no. 48. National Academy of Sciences, pp. 14906–14911, 2015. ista: de Vos M, Dawid A, Šunderlíková V, Tans S. 2015. Breaking evolutionary constraint with a tradeoff ratchet. PNAS. 112(48), 14906–14911. mla: de Vos, Marjon, et al. “Breaking Evolutionary Constraint with a Tradeoff Ratchet.” PNAS, vol. 112, no. 48, National Academy of Sciences, 2015, pp. 14906–11, doi:10.1073/pnas.1510282112. short: M. de Vos, A. Dawid, V. Šunderlíková, S. Tans, PNAS 112 (2015) 14906–14911. date_created: 2018-12-11T11:52:47Z date_published: 2015-12-01T00:00:00Z date_updated: 2021-01-12T06:51:40Z day: '01' department: - _id: ToBo doi: 10.1073/pnas.1510282112 intvolume: ' 112' issue: '48' language: - iso: eng month: '12' oa_version: None page: 14906 - 14911 publication: PNAS publication_status: published publisher: National Academy of Sciences publist_id: '5600' quality_controlled: '1' scopus_import: 1 status: public title: Breaking evolutionary constraint with a tradeoff ratchet type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 112 year: '2015' ... --- _id: '1581' abstract: - lang: eng text: In animal embryos, morphogen gradients determine tissue patterning and morphogenesis. Shyer et al. provide evidence that, during vertebrate gut formation, tissue folding generates graded activity of signals required for subsequent steps of gut growth and differentiation, thereby revealing an intriguing link between tissue morphogenesis and morphogen gradient formation. article_processing_charge: No author: - first_name: Mark Tobias full_name: Bollenbach, Mark Tobias id: 3E6DB97A-F248-11E8-B48F-1D18A9856A87 last_name: Bollenbach orcid: 0000-0003-4398-476X - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 citation: ama: Bollenbach MT, Heisenberg C-PJ. Gradients are shaping up. Cell. 2015;161(3):431-432. doi:10.1016/j.cell.2015.04.009 apa: Bollenbach, M. T., & Heisenberg, C.-P. J. (2015). Gradients are shaping up. Cell. Cell Press. https://doi.org/10.1016/j.cell.2015.04.009 chicago: Bollenbach, Mark Tobias, and Carl-Philipp J Heisenberg. “Gradients Are Shaping Up.” Cell. Cell Press, 2015. https://doi.org/10.1016/j.cell.2015.04.009. ieee: M. T. Bollenbach and C.-P. J. Heisenberg, “Gradients are shaping up,” Cell, vol. 161, no. 3. Cell Press, pp. 431–432, 2015. ista: Bollenbach MT, Heisenberg C-PJ. 2015. Gradients are shaping up. Cell. 161(3), 431–432. mla: Bollenbach, Mark Tobias, and Carl-Philipp J. Heisenberg. “Gradients Are Shaping Up.” Cell, vol. 161, no. 3, Cell Press, 2015, pp. 431–32, doi:10.1016/j.cell.2015.04.009. short: M.T. Bollenbach, C.-P.J. Heisenberg, Cell 161 (2015) 431–432. date_created: 2018-12-11T11:52:50Z date_published: 2015-04-23T00:00:00Z date_updated: 2022-08-25T13:56:10Z day: '23' department: - _id: ToBo - _id: CaHe doi: 10.1016/j.cell.2015.04.009 intvolume: ' 161' issue: '3' language: - iso: eng month: '04' oa_version: None page: 431 - 432 publication: Cell publication_status: published publisher: Cell Press publist_id: '5590' quality_controlled: '1' scopus_import: '1' status: public title: Gradients are shaping up type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 161 year: '2015' ... --- _id: '1586' abstract: - lang: eng text: Through metabolic engineering cyanobacteria can be employed in biotechnology. Combining the capacity for oxygenic photosynthesis and carbon fixation with an engineered metabolic pathway allows carbon-based product formation from CO2, light, and water directly. Such cyanobacterial 'cell factories' are constructed to produce biofuels, bioplastics, and commodity chemicals. Efforts of metabolic engineers and synthetic biologists allow the modification of the intermediary metabolism at various branching points, expanding the product range. The new biosynthesis routes 'tap' the metabolism ever more efficiently, particularly through the engineering of driving forces and utilization of cofactors generated during the light reactions of photosynthesis, resulting in higher product titers. High rates of carbon rechanneling ultimately allow an almost-complete allocation of fixed carbon to product above biomass. author: - first_name: Andreas full_name: Angermayr, Andreas id: 4677C796-F248-11E8-B48F-1D18A9856A87 last_name: Angermayr orcid: 0000-0001-8619-2223 - first_name: Aleix full_name: Gorchs, Aleix last_name: Gorchs - first_name: Klaas full_name: Hellingwerf, Klaas last_name: Hellingwerf citation: ama: Angermayr A, Gorchs A, Hellingwerf K. Metabolic engineering of cyanobacteria for the synthesis of commodity products. Trends in Biotechnology. 2015;33(6):352-361. doi:10.1016/j.tibtech.2015.03.009 apa: Angermayr, A., Gorchs, A., & Hellingwerf, K. (2015). Metabolic engineering of cyanobacteria for the synthesis of commodity products. Trends in Biotechnology. Elsevier. https://doi.org/10.1016/j.tibtech.2015.03.009 chicago: Angermayr, Andreas, Aleix Gorchs, and Klaas Hellingwerf. “Metabolic Engineering of Cyanobacteria for the Synthesis of Commodity Products.” Trends in Biotechnology. Elsevier, 2015. https://doi.org/10.1016/j.tibtech.2015.03.009. ieee: A. Angermayr, A. Gorchs, and K. Hellingwerf, “Metabolic engineering of cyanobacteria for the synthesis of commodity products,” Trends in Biotechnology, vol. 33, no. 6. Elsevier, pp. 352–361, 2015. ista: Angermayr A, Gorchs A, Hellingwerf K. 2015. Metabolic engineering of cyanobacteria for the synthesis of commodity products. Trends in Biotechnology. 33(6), 352–361. mla: Angermayr, Andreas, et al. “Metabolic Engineering of Cyanobacteria for the Synthesis of Commodity Products.” Trends in Biotechnology, vol. 33, no. 6, Elsevier, 2015, pp. 352–61, doi:10.1016/j.tibtech.2015.03.009. short: A. Angermayr, A. Gorchs, K. Hellingwerf, Trends in Biotechnology 33 (2015) 352–361. date_created: 2018-12-11T11:52:52Z date_published: 2015-06-01T00:00:00Z date_updated: 2021-01-12T06:51:46Z day: '01' department: - _id: ToBo doi: 10.1016/j.tibtech.2015.03.009 intvolume: ' 33' issue: '6' language: - iso: eng month: '06' oa_version: None page: 352 - 361 publication: Trends in Biotechnology publication_status: published publisher: Elsevier publist_id: '5585' quality_controlled: '1' scopus_import: 1 status: public title: Metabolic engineering of cyanobacteria for the synthesis of commodity products type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 33 year: '2015' ... --- _id: '1623' abstract: - lang: eng text: "Background\r\nPhotosynthetic cyanobacteria are attractive for a range of biotechnological applications including biofuel production. However, due to slow growth, screening of mutant libraries using microtiter plates is not feasible.\r\nResults\r\nWe present a method for high-throughput, single-cell analysis and sorting of genetically engineered l-lactate-producing strains of Synechocystis sp. PCC6803. A microfluidic device is used to encapsulate single cells in picoliter droplets, assay the droplets for l-lactate production, and sort strains with high productivity. We demonstrate the separation of low- and high-producing reference strains, as well as enrichment of a more productive l-lactate-synthesizing population after UV-induced mutagenesis. The droplet platform also revealed population heterogeneity in photosynthetic growth and lactate production, as well as the presence of metabolically stalled cells.\r\nConclusions\r\nThe workflow will facilitate metabolic engineering and directed evolution studies and will be useful in studies of cyanobacteria biochemistry and physiology.\r\n" article_number: '193' author: - first_name: Petter full_name: Hammar, Petter last_name: Hammar - first_name: Andreas full_name: Angermayr, Andreas id: 4677C796-F248-11E8-B48F-1D18A9856A87 last_name: Angermayr orcid: 0000-0001-8619-2223 - first_name: Staffan full_name: Sjostrom, Staffan last_name: Sjostrom - first_name: Josefin full_name: Van Der Meer, Josefin last_name: Van Der Meer - first_name: Klaas full_name: Hellingwerf, Klaas last_name: Hellingwerf - first_name: Elton full_name: Hudson, Elton last_name: Hudson - first_name: Hakaan full_name: Joensson, Hakaan last_name: Joensson citation: ama: Hammar P, Angermayr A, Sjostrom S, et al. Single-cell screening of photosynthetic growth and lactate production by cyanobacteria. Biotechnology for Biofuels. 2015;8(1). doi:10.1186/s13068-015-0380-2 apa: Hammar, P., Angermayr, A., Sjostrom, S., Van Der Meer, J., Hellingwerf, K., Hudson, E., & Joensson, H. (2015). Single-cell screening of photosynthetic growth and lactate production by cyanobacteria. Biotechnology for Biofuels. BioMed Central. https://doi.org/10.1186/s13068-015-0380-2 chicago: Hammar, Petter, Andreas Angermayr, Staffan Sjostrom, Josefin Van Der Meer, Klaas Hellingwerf, Elton Hudson, and Hakaan Joensson. “Single-Cell Screening of Photosynthetic Growth and Lactate Production by Cyanobacteria.” Biotechnology for Biofuels. BioMed Central, 2015. https://doi.org/10.1186/s13068-015-0380-2. ieee: P. Hammar et al., “Single-cell screening of photosynthetic growth and lactate production by cyanobacteria,” Biotechnology for Biofuels, vol. 8, no. 1. BioMed Central, 2015. ista: Hammar P, Angermayr A, Sjostrom S, Van Der Meer J, Hellingwerf K, Hudson E, Joensson H. 2015. Single-cell screening of photosynthetic growth and lactate production by cyanobacteria. Biotechnology for Biofuels. 8(1), 193. mla: Hammar, Petter, et al. “Single-Cell Screening of Photosynthetic Growth and Lactate Production by Cyanobacteria.” Biotechnology for Biofuels, vol. 8, no. 1, 193, BioMed Central, 2015, doi:10.1186/s13068-015-0380-2. short: P. Hammar, A. Angermayr, S. Sjostrom, J. Van Der Meer, K. Hellingwerf, E. Hudson, H. Joensson, Biotechnology for Biofuels 8 (2015). date_created: 2018-12-11T11:53:05Z date_published: 2015-11-25T00:00:00Z date_updated: 2021-01-12T06:52:04Z day: '25' ddc: - '570' department: - _id: ToBo doi: 10.1186/s13068-015-0380-2 file: - access_level: open_access checksum: 172b0b6f4eb2e5c22b7cec1d57dc0107 content_type: application/pdf creator: system date_created: 2018-12-12T10:10:11Z date_updated: 2020-07-14T12:45:07Z file_id: '4796' file_name: IST-2016-467-v1+1_s13068-015-0380-2.pdf file_size: 2914089 relation: main_file file_date_updated: 2020-07-14T12:45:07Z has_accepted_license: '1' intvolume: ' 8' issue: '1' language: - iso: eng month: '11' oa: 1 oa_version: Published Version publication: Biotechnology for Biofuels publication_status: published publisher: BioMed Central publist_id: '5537' pubrep_id: '467' quality_controlled: '1' scopus_import: 1 status: public title: Single-cell screening of photosynthetic growth and lactate production by cyanobacteria tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 8 year: '2015' ... --- _id: '1810' abstract: - lang: eng text: Combining antibiotics is a promising strategy for increasing treatment efficacy and for controlling resistance evolution. When drugs are combined, their effects on cells may be amplified or weakened, that is the drugs may show synergistic or antagonistic interactions. Recent work revealed the underlying mechanisms of such drug interactions by elucidating the drugs'; joint effects on cell physiology. Moreover, new treatment strategies that use drug combinations to exploit evolutionary tradeoffs were shown to affect the rate of resistance evolution in predictable ways. High throughput studies have further identified drug candidates based on their interactions with established antibiotics and general principles that enable the prediction of drug interactions were suggested. Overall, the conceptual and technical foundation for the rational design of potent drug combinations is rapidly developing. author: - first_name: Mark Tobias full_name: Bollenbach, Mark Tobias id: 3E6DB97A-F248-11E8-B48F-1D18A9856A87 last_name: Bollenbach orcid: 0000-0003-4398-476X citation: ama: 'Bollenbach MT. Antimicrobial interactions: Mechanisms and implications for drug discovery and resistance evolution. Current Opinion in Microbiology. 2015;27:1-9. doi:10.1016/j.mib.2015.05.008' apa: 'Bollenbach, M. T. (2015). Antimicrobial interactions: Mechanisms and implications for drug discovery and resistance evolution. Current Opinion in Microbiology. Elsevier. https://doi.org/10.1016/j.mib.2015.05.008' chicago: 'Bollenbach, Mark Tobias. “Antimicrobial Interactions: Mechanisms and Implications for Drug Discovery and Resistance Evolution.” Current Opinion in Microbiology. Elsevier, 2015. https://doi.org/10.1016/j.mib.2015.05.008.' ieee: 'M. T. Bollenbach, “Antimicrobial interactions: Mechanisms and implications for drug discovery and resistance evolution,” Current Opinion in Microbiology, vol. 27. Elsevier, pp. 1–9, 2015.' ista: 'Bollenbach MT. 2015. Antimicrobial interactions: Mechanisms and implications for drug discovery and resistance evolution. Current Opinion in Microbiology. 27, 1–9.' mla: 'Bollenbach, Mark Tobias. “Antimicrobial Interactions: Mechanisms and Implications for Drug Discovery and Resistance Evolution.” Current Opinion in Microbiology, vol. 27, Elsevier, 2015, pp. 1–9, doi:10.1016/j.mib.2015.05.008.' short: M.T. Bollenbach, Current Opinion in Microbiology 27 (2015) 1–9. date_created: 2018-12-11T11:54:08Z date_published: 2015-06-01T00:00:00Z date_updated: 2021-01-12T06:53:21Z day: '01' ddc: - '570' department: - _id: ToBo doi: 10.1016/j.mib.2015.05.008 ec_funded: 1 file: - access_level: open_access checksum: 1683bb0f42ef892a5b3b71a050d65d25 content_type: application/pdf creator: system date_created: 2018-12-12T10:17:23Z date_updated: 2020-07-14T12:45:17Z file_id: '5277' file_name: IST-2016-493-v1+1_1-s2.0-S1369527415000594-main.pdf file_size: 1047255 relation: main_file file_date_updated: 2020-07-14T12:45:17Z has_accepted_license: '1' intvolume: ' 27' language: - iso: eng month: '06' oa: 1 oa_version: Published Version page: 1 - 9 project: - _id: 25E9AF9E-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: P27201-B22 name: Revealing the mechanisms underlying drug interactions - _id: 25E83C2C-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '303507' name: Optimality principles in responses to antibiotics - _id: 25EB3A80-B435-11E9-9278-68D0E5697425 grant_number: RGP0042/2013 name: Revealing the fundamental limits of cell growth publication: Current Opinion in Microbiology publication_status: published publisher: Elsevier publist_id: '5298' pubrep_id: '493' quality_controlled: '1' scopus_import: 1 status: public title: 'Antimicrobial interactions: Mechanisms and implications for drug discovery and resistance evolution' tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 27 year: '2015' ...