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Wan J, Ding JL, Lu H. Microfluidic approach to correlate C. elegans neuronal functional aging and underlying changes of gene expression in mechanosensation. LAB ON A CHIP 2024; 24:2811-2824. [PMID: 38700452 DOI: 10.1039/d3lc01080e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
The aging process has broad physiological impacts, including a significant decline in sensory function, which threatens both physical health and quality of life. One ideal model to study aging, neuronal function, and gene expression is the nematode Caenorhabditis elegans, which has a short lifespan and relatively simple, thoroughly mapped nervous system and genome. Previous works have identified that mechanosensory neuronal structure changes with age, but importantly, the actual age-related changes in the function and health of neurons, as well as the underlying genetic mechanisms responsible for these declines, are not fully understood. While advanced techniques such as single-cell RNA-sequencing have been developed to quantify gene expression, it is difficult to relate this information to functional changes in aging due to a lack of tools available. To address these limitations, we present a platform capable of measuring both physiological function and its associated gene expression throughout the aging process in individuals. Using our pipeline, we investigate the age-related changes in function of the mechanosensing ALM neuron in C. elegans, as well as some relevant gene expression patterns (mec-4 and mec-10). Using a series of devices for animals of different ages, we examined subtle changes in neuronal function and found that while the magnitude of neuronal response to a large stimulus declines with age, sensory capability does not significantly decline with age; further, gene expression is well maintained throughout aging. Additionally, we examine PVD, a harsh-touch mechanosensory neuron, and find that it exhibits a similar age-related decline in magnitude of neuronal response. Together, our data demonstrate that our strategy is useful for identifying genetic factors involved in the decline in neuronal health. We envision that this framework could be applied to other systems as a useful tool for discovering new biology.
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Affiliation(s)
- Jason Wan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Jimmy L Ding
- Petit Institute for Bioengineering and Bioscience, Interdisciplinary BioEngineering Program, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Hang Lu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
- Petit Institute for Bioengineering and Bioscience, Interdisciplinary BioEngineering Program, Georgia Institute of Technology, Atlanta, GA 30332, USA.
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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2
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Chung T, Chang I, Kim S. Development of equation of motion deciphering locomotion including omega turns of Caenorhabditis elegans. eLife 2024; 12:RP92562. [PMID: 38682888 PMCID: PMC11057871 DOI: 10.7554/elife.92562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024] Open
Abstract
Locomotion is a fundamental behavior of Caenorhabditis elegans (C. elegans). Previous works on kinetic simulations of animals helped researchers understand the physical mechanisms of locomotion and the muscle-controlling principles of neuronal circuits as an actuator part. It has yet to be understood how C. elegans utilizes the frictional forces caused by the tension of its muscles to perform sequenced locomotive behaviors. Here, we present a two-dimensional rigid body chain model for the locomotion of C. elegans by developing Newtonian equations of motion for each body segment of C. elegans. Having accounted for friction-coefficients of the surrounding environment, elastic constants of C. elegans, and its kymogram from experiments, our kinetic model (ElegansBot) reproduced various locomotion of C. elegans such as, but not limited to, forward-backward-(omega turn)-forward locomotion constituting escaping behavior and delta-turn navigation. Additionally, ElegansBot precisely quantified the forces acting on each body segment of C. elegans to allow investigation of the force distribution. This model will facilitate our understanding of the detailed mechanism of various locomotive behaviors at any given friction-coefficients of the surrounding environment. Furthermore, as the model ensures the performance of realistic behavior, it can be used to research actuator-controller interaction between muscles and neuronal circuits.
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Affiliation(s)
- Taegon Chung
- Daegu Gyeongbuk Institute of Science and TechnologyDaeguRepublic of Korea
| | - Iksoo Chang
- Daegu Gyeongbuk Institute of Science and TechnologyDaeguRepublic of Korea
| | - Sangyeol Kim
- Daegu Gyeongbuk Institute of Science and TechnologyDaeguRepublic of Korea
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3
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Petersen EJ, Barrios AC, Henry TB, Johnson ME, Koelmans AA, Montoro Bustos AR, Matheson J, Roesslein M, Zhao J, Xing B. Potential Artifacts and Control Experiments in Toxicity Tests of Nanoplastic and Microplastic Particles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15192-15206. [PMID: 36240263 PMCID: PMC10476161 DOI: 10.1021/acs.est.2c04929] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/29/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
To fully understand the potential ecological and human health risks from nanoplastics and microplastics (NMPs) in the environment, it is critical to make accurate measurements. Similar to past research on the toxicology of engineered nanomaterials, a broad range of measurement artifacts and biases are possible when testing their potential toxicity. For example, antimicrobials and surfactants may be present in commercially available NMP dispersions, and these compounds may account for toxicity observed instead of being caused by exposure to the NMP particles. Therefore, control measurements are needed to assess potential artifacts, and revisions to the protocol may be needed to eliminate or reduce the artifacts. In this paper, we comprehensively review and suggest a next generation of control experiments to identify measurement artifacts and biases that can occur while performing NMP toxicity experiments. This review covers the broad range of potential NMP toxicological experiments, such as in vitro studies with a single cell type or complex 3-D tissue constructs, in vivo mammalian studies, and ecotoxicity experiments testing pelagic, sediment, and soil organisms. Incorporation of these control experiments can reduce the likelihood of false positive and false negative results and more accurately elucidate the potential ecological and human health risks of NMPs.
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Affiliation(s)
- Elijah. J. Petersen
- Material
Measurement Laboratory, National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Ana C. Barrios
- Material
Measurement Laboratory, National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Theodore B. Henry
- School
of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
- Department
of Forestry, Wildlife and Fisheries, University
of Tennessee, Knoxville, Tennessee 37996, United States
| | - Monique E. Johnson
- Material
Measurement Laboratory, National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Albert A. Koelmans
- Aquatic
Ecology and Water Quality Management group, Wageningen University & Research, 6700 AA Wageningen, The Netherlands
| | - Antonio R. Montoro Bustos
- Material
Measurement Laboratory, National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Joanna Matheson
- US
Consumer Product Safety Commission, 5 Research Place, Rockville, Maryland 20850, United States
| | - Matthias Roesslein
- Empa, Swiss
Federal Laboratories for Material Testing and Research, Particles-Biology
Interactions Laboratory, CH-9014 St. Gallen, Switzerland
| | - Jian Zhao
- Institute
of Coastal Environmental Pollution Control, Ministry of Education
Key Laboratory of Marine Environment and Ecology, and Frontiers Science
Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266100, China
| | - Baoshan Xing
- Stockbridge
School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States
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4
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Soni P, Anupom T, Lesanpezeshki L, Rahman M, Hewitt JE, Vellone M, Stodieck L, Blawzdziewicz J, Szewczyk NJ, Vanapalli SA. Microfluidics-integrated spaceflight hardware for measuring muscle strength of Caenorhabditis elegans on the International Space Station. NPJ Microgravity 2022; 8:50. [PMID: 36344513 PMCID: PMC9640571 DOI: 10.1038/s41526-022-00241-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022] Open
Abstract
Caenorhabditis elegans is a low-cost genetic model that has been flown to the International Space Station to investigate the influence of microgravity on changes in the expression of genes involved in muscle maintenance. These studies showed that genes that encode muscle attachment complexes have decreased expression under microgravity. However, it remains to be answered whether the decreased expression leads to concomitant changes in animal muscle strength, specifically across multiple generations. We recently reported the NemaFlex microfluidic device for the measurement of muscle strength of C. elegans (Rahman et al., Lab Chip, 2018). In this study, we redesign our original NemaFlex device and integrate it with flow control hardware for spaceflight investigations considering mixed animal culture, constraints on astronaut time, crew safety, and on-orbit operations. The technical advances we have made include (i) a microfluidic device design that allows animals of a given size to be sorted from unsynchronized cultures and housed in individual chambers, (ii) a fluid handling protocol for injecting the suspension of animals into the microfluidic device that prevents channel clogging, introduction of bubbles, and crowding of animals in the chambers, and (iii) a custom-built worm-loading apparatus interfaced with the microfluidic device that allows easy manipulation of the worm suspension and prevents fluid leakage into the surrounding environment. Collectively, these technical advances enabled the development of new microfluidics-integrated hardware for spaceflight studies in C. elegans. Finally, we report Earth-based validation studies to test this new hardware, which has led to it being flown to the International Space Station.
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Scharf A, Mitteldorf J, Armstead B, Schneider D, Jin H, Kocsisova Z, Tan CH, Sanchez F, Brady B, Ram N, DiAntonio GB, Wilson AM, Kornfeld K. A laboratory and simulation platform to integrate individual life history traits and population dynamics. NATURE COMPUTATIONAL SCIENCE 2022; 2:90-101. [PMID: 37981946 PMCID: PMC10655596 DOI: 10.1038/s43588-022-00190-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 01/06/2022] [Indexed: 11/21/2023]
Abstract
Understanding populations is important because they are a fundamental level of biological organization. Individual traits such as aging and lifespan interact in complex ways to determine birth and death and thereby influence population dynamics. However, we lack a deep understanding of the relationships between individual traits and population dynamics. To address this challenge, we established a laboratory population using the model organism C. elegans and an individual-based computational simulation informed by measurements of real worms. The simulation realistically models individual worms and the behavior of the laboratory population. To elucidate the role of aging in population dynamics, we analyzed old age as a cause of death and showed, using computer simulations, that it was influenced by maximum lifespan, rate of adult culling, and progeny number/food stability. Notably, populations displayed a tipping point for aging as the primary cause of adult death. Our work establishes a conceptual framework that could be used for better understanding why certain animals die of old age in the wild.
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Affiliation(s)
- Andrea Scharf
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Josh Mitteldorf
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Brinda Armstead
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Daniel Schneider
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - He Jin
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Zuzana Kocsisova
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Chieh-Hsiang Tan
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
- Current address: Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125, USA
| | - Francesca Sanchez
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Brian Brady
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Natasha Ram
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Gabriel B. DiAntonio
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
| | - Andrea M. Wilson
- Center for the Study of Collaboration, 9378 Olive Blvd., Ste 122, Saint Louis, MO 63132
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO 63110
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O'Connell KF. Cryopreservation of C. elegans and Other Nematodes with Dimethyl Sulfoxide and Trehalose. Methods Mol Biol 2022; 2468:43-49. [PMID: 35320559 DOI: 10.1007/978-1-0716-2181-3_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
One of the key attributes that has contributed to the popularity of Caenorhabditis elegans as a model system is its ability to survive freezing. By preserving stocks at ultralow temperature, researchers have been able to generate an unlimited number of strains without the burden of constantly maintaining them. This has facilitated the use of large-scale forward genetic screens and CRISPR-mediated genome editing where large numbers of novel and informative mutants can be generated. Traditionally, C. elegans and other nematodes were frozen using glycerol as a cryoprotectant. While effective, a large majority of animals do not survive a typical freeze-thaw cycle. Here I describe an alternative method based on the popular combination of DMSO and trehalose as a cryoprotectant. This method allows the survival of large numbers of worms and effectively protects most developmental stages including adults.
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Affiliation(s)
- Kevin F O'Connell
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes & Digestive and Kidney Diseases, Bethesda, MD, USA.
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7
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Chen WL, Ko H, Chuang HS, Raizen DM, Bau HH. Caenorhabditis elegans exhibits positive gravitaxis. BMC Biol 2021; 19:186. [PMID: 34517863 PMCID: PMC8439010 DOI: 10.1186/s12915-021-01119-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 08/04/2021] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Gravity plays an important role in most life forms on Earth. Yet, a complete molecular understanding of sensing and responding to gravity is lacking. While there are anatomical differences among animals, there is a remarkable conservation across phylogeny at the molecular level. Caenorhabditis elegans is suitable for gene discovery approaches that may help identify molecular mechanisms of gravity sensing. It is unknown whether C. elegans can sense the direction of gravity. RESULTS In aqueous solutions, motile C. elegans nematodes align their swimming direction with the gravity vector direction while immobile worms do not. The worms orient downward regardless of whether they are suspended in a solution less dense (downward sedimentation) or denser (upward sedimentation) than themselves. Gravitaxis is minimally affected by the animals' gait but requires sensory cilia and dopamine neurotransmission, as well as motility; it does not require genes that function in the body touch response. CONCLUSIONS Gravitaxis is not mediated by passive forces such as non-uniform mass distribution or hydrodynamic effects. Rather, it is mediated by active neural processes that involve sensory cilia and dopamine. C. elegans provides a genetically tractable system to study molecular and neural mechanisms of gravity sensing.
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Affiliation(s)
- Wei-Long Chen
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA USA
- Department of Biomedical Engineering, National Cheng Kung University (NCKU), Tainan, Taiwan
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Hungtang Ko
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA USA
- Current Address: School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA USA
| | - Han-Sheng Chuang
- Department of Biomedical Engineering, National Cheng Kung University (NCKU), Tainan, Taiwan
| | - David M. Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Haim H. Bau
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA USA
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8
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Sub-nanowatt resolution direct calorimetry for probing real-time metabolic activity of individual C. elegans worms. Nat Commun 2020; 11:2983. [PMID: 32532993 PMCID: PMC7293274 DOI: 10.1038/s41467-020-16690-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 05/13/2020] [Indexed: 11/25/2022] Open
Abstract
Calorimetry has been widely used in metabolic studies, but direct measurements from individual small biological model organisms such as C. elegans or isolated single cells have been limited by poor sensitivity of existing techniques and difficulties in resolving very small heat outputs. Here, by careful thermal engineering, we developed a robust, highly sensitive and bio-compatible calorimetric platform that features a resolution of ~270 pW—more than a 500-fold improvement over the most sensitive calorimeter previously used for measuring the metabolic heat output of C. elegans. Using this calorimeter, we demonstrate time-resolved metabolic measurements of single C. elegans worms from larval to adult stages. Further, we show that the metabolic output is significantly lower in long-lived C. elegans daf-2 mutants. These demonstrations clearly highlight the broad potential of this tool for studying the role of metabolism in disease, development and aging of small model organisms and single cells. Calorimetry is widely used for metabolic studies, but measurements of single cells and small organisms are limited by the sensitivity of current techniques. Here the authors develop a sensitive platform for performing time-resolved metabolic measurements of single C. elegans worms from larval to adult stages.
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9
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Chakrabortty T, Suman A, Gupta A, Singh V, Varma M. Null model exhibiting synchronized dynamics in uncoupled oscillators. Phys Rev E 2019; 99:052410. [PMID: 31212412 DOI: 10.1103/physreve.99.052410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Indexed: 06/09/2023]
Abstract
The phenomenon of phase synchronization of oscillatory systems, arising out of feedback coupling is ubiquitous across physics and biology. In noisy, complex systems, one generally observes transient epochs of synchronization followed by nonsynchronous dynamics. How does one guarantee that the observed transient epochs of synchronization are arising from an underlying feedback mechanism and not from some peculiar statistical properties of the system? This question is particularly important for complex biological systems, where the search for a nonexistent feedback mechanism may turn out to be an enormous waste of resources. In this article, we propose a null model for synchronization, motivated by expectations on the dynamical behavior of biological systems, to provide a quantitative measure of the confidence with which one can infer the existence of a feedback mechanism based on observation of transient synchronized behavior. We demonstrate the application of our null model to the phenomenon of gait synchronization in free-swimming nematodes, Caenorhabditis elegans.
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Affiliation(s)
- Tuhin Chakrabortty
- Center for Nano Science and Engineering, Indian Institute of Science, Bangalore, India
| | - Akash Suman
- Center for Nano Science and Engineering, Indian Institute of Science, Bangalore, India
| | - Anjali Gupta
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India
| | - Varsha Singh
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
| | - Manoj Varma
- Center for Nano Science and Engineering, Indian Institute of Science, Bangalore, India
- Robert Bosch Centre for Cyber-Physical Systems, Indian Institute of Science, Bangalore, India
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Petersen EJ, Mortimer M, Burgess RM, Handy R, Hanna S, Ho KT, Johnson M, Loureiro S, Selck H, Scott-Fordsmand JJ, Spurgeon D, Unrine J, van den Brink N, Wang Y, White J, Holden P. Strategies for robust and accurate experimental approaches to quantify nanomaterial bioaccumulation across a broad range of organisms. ENVIRONMENTAL SCIENCE. NANO 2019; 6:10.1039/C8EN01378K. [PMID: 31579514 PMCID: PMC6774209 DOI: 10.1039/c8en01378k] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
One of the key components for environmental risk assessment of engineered nanomaterials (ENMs) is data on bioaccumulation potential. Accurately measuring bioaccumulation can be critical for regulatory decision making regarding material hazard and risk, and for understanding the mechanism of toxicity. This perspective provides expert guidance for performing ENM bioaccumulation measurements across a broad range of test organisms and species. To accomplish this aim, we critically evaluated ENM bioaccumulation within three categories of organisms: single-celled species, multicellular species excluding plants, and multicellular plants. For aqueous exposures of suspended single-celled and small multicellular species, it is critical to perform a robust procedure to separate suspended ENMs and small organisms to avoid overestimating bioaccumulation. For many multicellular organisms, it is essential to differentiate between the ENMs adsorbed to external surfaces or in the digestive tract and the amount absorbed across epithelial tissues. For multicellular plants, key considerations include how exposure route and the role of the rhizosphere may affect the quantitative measurement of uptake, and that the efficiency of washing procedures to remove loosely attached ENMs to the roots is not well understood. Within each organism category, case studies are provided to illustrate key methodological considerations for conducting robust bioaccumulation experiments for different species within each major group. The full scope of ENM bioaccumulation measurements and interpretations are discussed including conducting the organism exposure, separating organisms from the ENMs in the test media after exposure, analytical methods to quantify ENMs in the tissues or cells, and modeling the ENM bioaccumulation results. One key finding to improve bioaccumulation measurements was the critical need for further analytical method development to identify and quantify ENMs in complex matrices. Overall, the discussion, suggestions, and case studies described herein will help improve the robustness of ENM bioaccumulation studies.
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Affiliation(s)
- Elijah J. Petersen
- Material Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD 20899
| | - Monika Mortimer
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California 93106, United States
| | - Robert M. Burgess
- US Environmental Protection Agency, Atlantic Ecology Division, 27 Tarzwell Dr., Narragansett, RI 02882
| | - Richard Handy
- Plymouth University, School of Biological Sciences, United Kingdom
| | - Shannon Hanna
- Material Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD 20899
| | - Kay T. Ho
- US Environmental Protection Agency, Atlantic Ecology Division, 27 Tarzwell Dr., Narragansett, RI 02882
| | - Monique Johnson
- Material Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD 20899
| | - Susana Loureiro
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Henriette Selck
- Roskilde University, Dept. of Science and Environment, Denmark
| | | | - David Spurgeon
- Centre for Ecology and Hydrology, Maclean Building, Wallingford, Oxfordshire, OX10 8BB, United Kingdom
| | - Jason Unrine
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546, USA
| | - Nico van den Brink
- Department of Toxicology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Ying Wang
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California 93106, United States
| | - Jason White
- Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, United States
| | - Patricia Holden
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California 93106, United States
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11
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Acoustic Compressibility of Caenorhabditis elegans. Biophys J 2018; 115:1817-1825. [PMID: 30314654 DOI: 10.1016/j.bpj.2018.08.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/13/2018] [Accepted: 08/20/2018] [Indexed: 02/03/2023] Open
Abstract
The acoustic compressibility of Caenorhabditis elegans is a necessary parameter for further understanding the underlying physics of acoustic manipulation techniques of this widely used model organism in biological sciences. In this work, numerical simulations were combined with experimental trajectory velocimetry of L1 C. elegans larvae to estimate the acoustic compressibility of C. elegans. A method based on bulk acoustic wave acoustophoresis was used for trajectory velocimetry experiments in a microfluidic channel. The model-based data analysis took into account the different sizes and shapes of L1 C. elegans larvae (255 ± 26 μm in length and 15 ± 2 μm in diameter). Moreover, the top and bottom walls of the microfluidic channel were considered in the hydrodynamic drag coefficient calculations, for both the C. elegans and the calibration particles. The hydrodynamic interaction between the specimen and the channel walls was further minimized by acoustically levitating the C. elegans and the particles to the middle of the measurement channel. Our data suggest an acoustic compressibility κCe of 430 TPa-1 with an uncertainty range of ±20 TPa-1 for C. elegans, a much lower value than what was previously reported for adult C. elegans using static methods. Our estimated compressibility is consistent with the relative volume fraction of lipids and proteins that would mainly make up for the body of C. elegans. This work is a departing point for practical engineering and design criteria for integrated acoustofluidic devices for biological applications.
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12
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Yuan J, Ko H, Raizen DM, Bau HH. Terrain following and applications: Caenorhabditis elegans swims along the floor using a bump and undulate strategy. J R Soc Interface 2017; 13:rsif.2016.0612. [PMID: 27903784 DOI: 10.1098/rsif.2016.0612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/10/2016] [Indexed: 11/12/2022] Open
Abstract
Nematodes such as Caenorhabditis elegans are heavier than water. When submerged in water, they settle to the bottom surface. Observations reveal that the animals do not lie flat on the bottom surface, but remain substantially suspended above the surface through continuous collisions with the surface, while maintaining their swimming gaits. Consequently, the swimming animals follow the bottom surface topography. When the bottom surface is inclined, the animals swim up or down along the incline. As the magnitude of the gravitational force can be easily estimated, this behaviour provides a convenient means to estimate the animal's propulsive thrust. The animals' tendency to follow the surface topography provides a means to control the swimmers' trajectories and direction of motion, which we demonstrate with a saw tooth-like ratchet that biases the animals to swim in a selected direction. The animals can also serve as surface topography probes since their residence time as a function of position provides information on surface features. Finally, we take advantage of surface following to construct a simple motility-based sorter that can sort animals based on genotype and state of health.
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Affiliation(s)
- Jinzhou Yuan
- Department of Mechanical Engineering and Applied Mechanics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hungtang Ko
- Department of Mechanical Engineering and Applied Mechanics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David M Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Haim H Bau
- Department of Mechanical Engineering and Applied Mechanics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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13
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Zhuo W, Lu H, McGrath PT. Microfluidic platform with spatiotemporally controlled micro-environment for studying long-term C. elegans developmental arrests. LAB ON A CHIP 2017; 17:1826-1833. [PMID: 28466940 PMCID: PMC5521175 DOI: 10.1039/c6lc01573e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Animals' long-term survival is dependent on their ability to sense, filter and respond to their environment at multiple timescales. For example, during development, animals integrate environmental information, which can then modulate adult behavior and developmental trajectory. The neural and molecular mechanisms that underlie these changes are poorly understood. C. elegans is a powerful model organism to study such mechanisms; however, conventional plate-based culturing techniques are limited in their ability to consistently control and modulate an animal's environmental conditions. To address this need, we developed a microfluidics-based experimental platform capable of long-term culture of populations of developing C. elegans covering the L1 larval stage to adulthood, while achieving spatial consistency and temporal control of their environment. To prevent bacterial accumulation and maintain optimal flow characteristics and nutrient consistency over the operational period of over one hundred and fifty hours, several features of the microfluidic system and the peripheral equipment were optimized. By manipulating food and pheromone exposure over several days, we were able to demonstrate environmental-dependent changes to growth rate and entry to dauer, an alternative developmental state. We envision this system to be useful in studying the mechanisms underlying long timescale changes to behavior and development in response to environmental changes.
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Affiliation(s)
- Weipeng Zhuo
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100
- The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA
| | - Patrick T. McGrath
- The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
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14
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Johnson ME, Hanna SK, Montoro Bustos AR, Sims CM, Elliott LCC, Lingayat A, Johnston AC, Nikoobakht B, Elliott JT, Holbrook RD, Scott KCK, Murphy KE, Petersen EJ, Yu LL, Nelson BC. Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis. ACS NANO 2017; 11:526-540. [PMID: 27983787 PMCID: PMC5459480 DOI: 10.1021/acsnano.6b06582] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
For environmental studies assessing uptake of orally ingested engineered nanoparticles (ENPs), a key step in ensuring accurate quantification of ingested ENPs is efficient separation of the organism from ENPs that are either nonspecifically adsorbed to the organism and/or suspended in the dispersion following exposure. Here, we measure the uptake of 30 and 60 nm gold nanoparticles (AuNPs) by the nematode, Caenorhabditis elegans, using a sucrose density gradient centrifugation protocol to remove noningested AuNPs. Both conventional inductively coupled plasma mass spectrometry (ICP-MS) and single particle (sp)ICP-MS are utilized to measure the total mass and size distribution, respectively, of ingested AuNPs. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) imaging confirmed that traditional nematode washing procedures were ineffective at removing excess suspended and/or adsorbed AuNPs after exposure. Water rinsing procedures had AuNP removal efficiencies ranging from 57 to 97% and 22 to 83%, while the sucrose density gradient procedure had removal efficiencies of 100 and 93 to 98%, respectively, for the 30 and 60 nm AuNP exposure conditions. Quantification of total Au uptake was performed following acidic digestion of nonexposed and Au-exposed nematodes, whereas an alkaline digestion procedure was optimized for the liberation of ingested AuNPs for spICP-MS characterization. Size distributions and particle number concentrations were determined for AuNPs ingested by nematodes with corresponding confirmation of nematode uptake via high-pressure freezing/freeze substitution resin preparation and large-area SEM imaging. Methods for the separation and in vivo quantification of ENPs in multicellular organisms will facilitate robust studies of ENP uptake, biotransformation, and hazard assessment in the environment.
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Affiliation(s)
- Monique E Johnson
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Shannon K Hanna
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Antonio R Montoro Bustos
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Christopher M Sims
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Lindsay C C Elliott
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Akshay Lingayat
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Adrian C Johnston
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Babak Nikoobakht
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - John T Elliott
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - R David Holbrook
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Keana C K Scott
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Karen E Murphy
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Elijah J Petersen
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Lee L Yu
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Bryant C Nelson
- Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
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15
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Ahmed D, Ozcelik A, Bojanala N, Nama N, Upadhyay A, Chen Y, Hanna-Rose W, Huang TJ. Rotational manipulation of single cells and organisms using acoustic waves. Nat Commun 2016; 7:11085. [PMID: 27004764 PMCID: PMC4814581 DOI: 10.1038/ncomms11085] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 02/19/2016] [Indexed: 12/18/2022] Open
Abstract
The precise rotational manipulation of single cells or organisms is invaluable to many applications in biology, chemistry, physics and medicine. In this article, we describe an acoustic-based, on-chip manipulation method that can rotate single microparticles, cells and organisms. To achieve this, we trapped microbubbles within predefined sidewall microcavities inside a microchannel. In an acoustic field, trapped microbubbles were driven into oscillatory motion generating steady microvortices which were utilized to precisely rotate colloids, cells and entire organisms (that is, C. elegans). We have tested the capabilities of our method by analysing reproductive system pathologies and nervous system morphology in C. elegans. Using our device, we revealed the underlying abnormal cell fusion causing defective vulval morphology in mutant worms. Our acoustofluidic rotational manipulation (ARM) technique is an easy-to-use, compact, and biocompatible method, permitting rotation regardless of optical, magnetic or electrical properties of the sample under investigation. The precise rotational manipulation of single cells is technically challenging and relies on the optical, magnetic and electrical properties of the biospecimen. Here the authors develop an acoustic-based, on-chip manipulation method that can rotate single microparticles, cells and organisms.
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Affiliation(s)
- Daniel Ahmed
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Adem Ozcelik
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Nagagireesh Bojanala
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Nitesh Nama
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Awani Upadhyay
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yuchao Chen
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Wendy Hanna-Rose
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Tony Jun Huang
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Department of Bioengineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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16
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Abstract
The compact nervous system of Caenorhabditis elegans and its genetic tractability are features that make this organism highly suitable for investigating energy balance in an animal system. Here, we focus on molecular components and organizational principles emerging from the investigation of pathways that largely originate in the nervous system and regulate feeding behavior but also peripheral fat regulation through neuroendocrine signaling. We provide an overview of studies aimed at understanding how C. elegans integrate internal and external cues in feeding behavior. We highlight some of the similarities and differences in energy balance between C. elegans and mammals. We also provide our perspective on unresolved issues, both conceptual and technical, that we believe have hampered critical evaluation of findings relevant to fat regulation in C. elegans.
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Affiliation(s)
- George A Lemieux
- Department of Physiology, University of California, San Francisco, California 94158;
| | - Kaveh Ashrafi
- Department of Physiology, University of California, San Francisco, California 94158;
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17
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Yuan J, Zhou J, Raizen DM, Bau HH. High-throughput, motility-based sorter for microswimmers such as C. elegans. LAB ON A CHIP 2015; 15:2790-8. [PMID: 26008643 PMCID: PMC4470807 DOI: 10.1039/c5lc00305a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Animal motility varies with genotype, disease, aging, and environmental conditions. In many studies, it is desirable to carry out high throughput motility-based sorting to isolate rare animals for, among other things, forward genetic screens to identify genetic pathways that regulate phenotypes of interest. Many commonly used screening processes are labor-intensive, lack sensitivity, and require extensive investigator training. Here, we describe a sensitive, high throughput, automated, motility-based method for sorting nematodes. Our method is implemented in a simple microfluidic device capable of sorting thousands of animals per hour per module, and is amenable to parallelism. The device successfully enriches for known C. elegans motility mutants. Furthermore, using this device, we isolate low-abundance mutants capable of suppressing the somnogenic effects of the flp-13 gene, which regulates C. elegans sleep. By performing genetic complementation tests, we demonstrate that our motility-based sorting device efficiently isolates mutants for the same gene identified by tedious visual inspection of behavior on an agar surface. Therefore, our motility-based sorter is capable of performing high throughput gene discovery approaches to investigate fundamental biological processes.
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Affiliation(s)
- Jinzhou Yuan
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
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