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Effects of essential oil components exposure on biological parameters of Caenorhabditis elegans. Food Chem Toxicol 2021; 159:112763. [PMID: 34896182 DOI: 10.1016/j.fct.2021.112763] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/03/2021] [Accepted: 12/06/2021] [Indexed: 12/17/2022]
Abstract
The extensive use of essential oil components in an increasing number of applications can substantially enhance exposure to these compounds, which leads to potential health and environmental hazards. This work aimed to evaluate the toxicity of four widely used essential oil components (carvacrol, eugenol, thymol, vanillin) using the in vivo model Caenorhabditis elegans. For this purpose, the LC50 value of acute exposure to these components was first established; then the effect of sublethal concentrations on nematodes' locomotion behaviour, reproduction, heat and oxidative stress resistance and chemotaxis was evaluated. The results showed that all the components had a concentration-dependent effect on nematode survival at moderate to high concentrations. Carvacrol and thymol were the two most toxic compounds, while vanillin had the mildest toxicological effect. Reproduction resulted in a more sensitive endpoint than lethality to evaluate toxicity. Only pre-exposure to carvacrol and eugenol at the highest tested sublethal concentrations conferred worms oxidative stress resistance. However, at these and lower concentrations, both components induced reproductive toxicity. Our results evidence that these compounds can be toxic at lower doses than those required for their biological action. These findings highlight the need for a specific toxicological assessment of every EOC application.
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Giong HK, Subramanian M, Yu K, Lee JS. Non-Rodent Genetic Animal Models for Studying Tauopathy: Review of Drosophila, Zebrafish, and C. elegans Models. Int J Mol Sci 2021; 22:8465. [PMID: 34445171 PMCID: PMC8395099 DOI: 10.3390/ijms22168465] [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: 06/30/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 12/12/2022] Open
Abstract
Tauopathy refers to a group of progressive neurodegenerative diseases, including frontotemporal lobar degeneration and Alzheimer's disease, which correlate with the malfunction of microtubule-associated protein Tau (MAPT) due to abnormal hyperphosphorylation, leading to the formation of intracellular aggregates in the brain. Despite extensive efforts to understand tauopathy and develop an efficient therapy, our knowledge is still far from complete. To find a solution for this group of devastating diseases, several animal models that mimic diverse disease phenotypes of tauopathy have been developed. Rodents are the dominating tauopathy models because of their similarity to humans and established disease lines, as well as experimental approaches. However, powerful genetic animal models using Drosophila, zebrafish, and C. elegans have also been developed for modeling tauopathy and have contributed to understanding the pathophysiology of tauopathy. The success of these models stems from the short lifespans, versatile genetic tools, real-time in-vivo imaging, low maintenance costs, and the capability for high-throughput screening. In this review, we summarize the main findings on mechanisms of tauopathy and discuss the current tauopathy models of these non-rodent genetic animals, highlighting their key advantages and limitations in tauopathy research.
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Affiliation(s)
- Hoi-Khoanh Giong
- Disease Target Structure Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea; (H.-K.G.); (M.S.)
- KRIBB School, University of Science and Technology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea
- Dementia DTC R&D Convergence Program, KIST, Hwarang-ro 14 gil 5, Seongbuk-gu, Seoul 02792, Korea
| | - Manivannan Subramanian
- Disease Target Structure Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea; (H.-K.G.); (M.S.)
- Dementia DTC R&D Convergence Program, KIST, Hwarang-ro 14 gil 5, Seongbuk-gu, Seoul 02792, Korea
| | - Kweon Yu
- Disease Target Structure Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea; (H.-K.G.); (M.S.)
- KRIBB School, University of Science and Technology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea
- Dementia DTC R&D Convergence Program, KIST, Hwarang-ro 14 gil 5, Seongbuk-gu, Seoul 02792, Korea
| | - Jeong-Soo Lee
- Disease Target Structure Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea; (H.-K.G.); (M.S.)
- KRIBB School, University of Science and Technology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea
- Dementia DTC R&D Convergence Program, KIST, Hwarang-ro 14 gil 5, Seongbuk-gu, Seoul 02792, Korea
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Stegeman GW, Medina D, Cutter AD, Ryu WS. Neuro-genetic plasticity of Caenorhabditis elegans behavioral thermal tolerance. BMC Neurosci 2019; 20:26. [PMID: 31182018 PMCID: PMC6558720 DOI: 10.1186/s12868-019-0510-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/03/2019] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Animal responses to thermal stimuli involve intricate contributions of genetics, neurobiology and physiology, with temperature variation providing a pervasive environmental factor for natural selection. Thermal behavior thus exemplifies a dynamic trait that requires non-trivial phenotypic summaries to appropriately capture the trait in response to a changing environment. To characterize the deterministic and plastic components of thermal responses, we developed a novel micro-droplet assay of nematode behavior that permits information-dense summaries of dynamic behavioral phenotypes as reaction norms in response to increasing temperature (thermal tolerance curves, TTC). RESULTS We found that C. elegans TTCs shift predictably with rearing conditions and developmental stage, with significant differences between distinct wildtype genetic backgrounds. Moreover, after screening TTCs for 58 C. elegans genetic mutant strains, we determined that genes affecting thermosensation, including cmk-1 and tax-4, potentially play important roles in the behavioral control of locomotion at high temperature, implicating neural decision-making in TTC shape rather than just generalized physiological limits. However, expression of the transient receptor potential ion channel TRPA-1 in the nervous system is not sufficient to rescue rearing-dependent plasticity in TTCs conferred by normal expression of this gene, indicating instead a role for intestinal signaling involving TRPA-1 in the adaptive plasticity of thermal performance. CONCLUSIONS These results implicate nervous system and non-nervous system contributions to behavior, in addition to basic cellular physiology, as key mediators of evolutionary responses to selection from temperature variation in nature.
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Affiliation(s)
- Gregory W Stegeman
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Denise Medina
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
- Department of Physics, University of Toronto, Toronto, Canada
| | - Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.
| | - William S Ryu
- Department of Physics, University of Toronto, Toronto, Canada.
- Donnelly Centre, University of Toronto, Toronto, ON, M5S3E1, Canada.
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Rahman M, Hewitt JE, Van-Bussel F, Edwards H, Blawzdziewicz J, Szewczyk NJ, Driscoll M, Vanapalli SA. NemaFlex: a microfluidics-based technology for standardized measurement of muscular strength of C. elegans. LAB ON A CHIP 2018; 18:2187-2201. [PMID: 29892747 PMCID: PMC6057834 DOI: 10.1039/c8lc00103k] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Muscle strength is a functional measure of quality of life in humans. Declines in muscle strength are manifested in diseases as well as during inactivity, aging, and space travel. With conserved muscle biology, the simple genetic model C. elegans is a high throughput platform in which to identify molecular mechanisms causing muscle strength loss and to develop interventions based on diet, exercise, and drugs. In the clinic, standardized strength measures are essential to quantitate changes in patients; however, analogous standards have not been recapitulated in the C. elegans model since force generation fluctuates based on animal behavior and locomotion. Here, we report a microfluidics-based system for strength measurement that we call 'NemaFlex', based on pillar deflection as the nematode crawls through a forest of pillars. We have optimized the micropillar forest design and identified robust measurement conditions that yield a measure of strength that is independent of behavior and gait. Validation studies using a muscle contracting agent and mutants confirm that NemaFlex can reliably score muscular strength in C. elegans. Additionally, we report a scaling factor to account for animal size that is consistent with a biomechanics model and enables comparative strength studies of mutants. Taken together, our findings anchor NemaFlex for applications in genetic and drug screens, for defining molecular and cellular circuits of neuromuscular function, and for dissection of degenerative processes in disuse, aging, and disease.
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Affiliation(s)
- Mizanur Rahman
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409, USA.
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5
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Partridge FA, Brown AE, Buckingham SD, Willis NJ, Wynne GM, Forman R, Else KJ, Morrison AA, Matthews JB, Russell AJ, Lomas DA, Sattelle DB. An automated high-throughput system for phenotypic screening of chemical libraries on C. elegans and parasitic nematodes. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2017; 8:8-21. [PMID: 29223747 PMCID: PMC5734697 DOI: 10.1016/j.ijpddr.2017.11.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/23/2017] [Accepted: 11/27/2017] [Indexed: 11/16/2022]
Abstract
Parasitic nematodes infect hundreds of millions of people and farmed livestock. Further, plant parasitic nematodes result in major crop damage. The pipeline of therapeutic compounds is limited and parasite resistance to the existing anthelmintic compounds is a global threat. We have developed an INVertebrate Automated Phenotyping Platform (INVAPP) for high-throughput, plate-based chemical screening, and an algorithm (Paragon) which allows screening for compounds that have an effect on motility and development of parasitic worms. We have validated its utility by determining the efficacy of a panel of known anthelmintics against model and parasitic nematodes: Caenorhabditis elegans, Haemonchus contortus, Teladorsagia circumcincta, and Trichuris muris. We then applied the system to screen the Pathogen Box chemical library in a blinded fashion and identified compounds already known to have anthelmintic or anti-parasitic activity, including tolfenpyrad, auranofin, and mebendazole; and 14 compounds previously undescribed as anthelmintics, including benzoxaborole and isoxazole chemotypes. This system offers an effective, high-throughput system for the discovery of novel anthelmintics.
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Affiliation(s)
- Frederick A Partridge
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Anwen E Brown
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Steven D Buckingham
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Nicky J Willis
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Graham M Wynne
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Ruth Forman
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Kathryn J Else
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Alison A Morrison
- Moredun Research Institute, Pentland Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, United Kingdom
| | - Jacqueline B Matthews
- Moredun Research Institute, Pentland Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, United Kingdom
| | - Angela J Russell
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom; Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, United Kingdom
| | - David A Lomas
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
| | - David B Sattelle
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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Wolstenholme AJ, Maclean MJ, Coates R, McCoy CJ, Reaves BJ. How do the macrocyclic lactones kill filarial nematode larvae? INVERTEBRATE NEUROSCIENCE 2016; 16:7. [PMID: 27279086 DOI: 10.1007/s10158-016-0190-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/30/2016] [Indexed: 12/17/2022]
Abstract
The macrocyclic lactones (MLs) are one of the few classes of drug used in the control of the human filarial infections, onchocerciasis and lymphatic filariasis, and the only one used to prevent heartworm disease in dogs and cats. Despite their importance in preventing filarial diseases, the way in which the MLs work against these parasites is unclear. In vitro measurements of nematode motility have revealed a large discrepancy between the maximum plasma concentrations achieved after drug administration and the amounts required to paralyze worms. Recent evidence has shed new light on the likely functions of the ML target, glutamate-gated chloride channels, in filarial nematodes and supports the hypothesis that the rapid clearance of microfilariae that follows treatment involves the host immune system.
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Affiliation(s)
- Adrian J Wolstenholme
- Department of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA. .,Department of Infectious Diseases, College of Veterinary Medicine, 501 D. W. Brooks Drive, Athens, GA, 30602, USA.
| | - Mary J Maclean
- Department of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA
| | - Ruby Coates
- Department of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA.,Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
| | - Ciaran J McCoy
- Department of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA.,School of Biological Sciences, Medical Biology Centre, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, UK
| | - Barbara J Reaves
- Department of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, 30602, USA
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Angstman NB, Frank HG, Schmitz C. Advanced Behavioral Analyses Show that the Presence of Food Causes Subtle Changes in C. elegans Movement. Front Behav Neurosci 2016; 10:60. [PMID: 27065825 PMCID: PMC4814519 DOI: 10.3389/fnbeh.2016.00060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 03/14/2016] [Indexed: 11/13/2022] Open
Abstract
As a widely used and studied model organism, Caenorhabditis elegans worms offer the ability to investigate implications of behavioral change. Although, investigation of C. elegans behavioral traits has been shown, analysis is often narrowed down to measurements based off a single point, and thus cannot pick up on subtle behavioral and morphological changes. In the present study videos were captured of four different C. elegans strains grown in liquid cultures and transferred to NGM-agar plates with an E. coli lawn or with no lawn. Using an advanced software, WormLab, the full skeleton and outline of worms were tracked to determine whether the presence of food affects behavioral traits. In all seven investigated parameters, statistically significant differences were found in worm behavior between those moving on NGM-agar plates with an E. coli lawn and NGM-agar plates with no lawn. Furthermore, multiple test groups showed differences in interaction between variables as the parameters that significantly correlated statistically with speed of locomotion varied. In the present study, we demonstrate the validity of a model to analyze C. elegans behavior beyond simple speed of locomotion. The need to account for a nested design while performing statistical analyses in similar studies is also demonstrated. With extended analyses, C. elegans behavioral change can be investigated with greater sensitivity, which could have wide utility in fields such as, but not limited to, toxicology, drug discovery, and RNAi screening.
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Affiliation(s)
- Nicholas B Angstman
- Department of Neuroanatomy, Ludwig-Maximilians University of Munich Munich, Germany
| | - Hans-Georg Frank
- Department of Neuroanatomy, Ludwig-Maximilians University of Munich Munich, Germany
| | - Christoph Schmitz
- Department of Neuroanatomy, Ludwig-Maximilians University of Munich Munich, Germany
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8
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Buckingham SD, Partridge FA, Sattelle DB. Automated, high-throughput, motility analysis in Caenorhabditis elegans and parasitic nematodes: Applications in the search for new anthelmintics. Int J Parasitol Drugs Drug Resist 2014; 4:226-32. [PMID: 25516833 PMCID: PMC4266775 DOI: 10.1016/j.ijpddr.2014.10.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The scale of the damage worldwide to human health, animal health and agricultural crops resulting from parasitic nematodes, together with the paucity of treatments and the threat of developing resistance to the limited set of widely-deployed chemical tools, underlines the urgent need to develop novel drugs and chemicals to control nematode parasites. Robust chemical screens which can be automated are a key part of that discovery process. Hitherto, the successful automation of nematode behaviours has been a bottleneck in the chemical discovery process. As the measurement of nematode motility can provide a direct scalar readout of the activity of the neuromuscular system and an indirect measure of the health of the animal, this omission is acute. Motility offers a useful assay for high-throughput, phenotypic drug/chemical screening and several recent developments have helped realise, at least in part, the potential of nematode-based drug screening. Here we review the challenges encountered in automating nematode motility and some important developments in the application of machine vision, statistical imaging and tracking approaches which enable the automated characterisation of nematode movement. Such developments facilitate automated screening for new drugs and chemicals aimed at controlling human and animal nematode parasites (anthelmintics) and plant nematode parasites (nematicides).
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Affiliation(s)
| | | | - David B. Sattelle
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, Cruciform Building, Gower Street, London WC1E 6BT, United Kingdom
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Restif C, Ibáñez-Ventoso C, Vora MM, Guo S, Metaxas D, Driscoll M. CeleST: computer vision software for quantitative analysis of C. elegans swim behavior reveals novel features of locomotion. PLoS Comput Biol 2014; 10:e1003702. [PMID: 25033081 PMCID: PMC4102393 DOI: 10.1371/journal.pcbi.1003702] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 05/19/2014] [Indexed: 11/18/2022] Open
Abstract
In the effort to define genes and specific neuronal circuits that control behavior and plasticity, the capacity for high-precision automated analysis of behavior is essential. We report on comprehensive computer vision software for analysis of swimming locomotion of C. elegans, a simple animal model initially developed to facilitate elaboration of genetic influences on behavior. C. elegans swim test software CeleST tracks swimming of multiple animals, measures 10 novel parameters of swim behavior that can fully report dynamic changes in posture and speed, and generates data in several analysis formats, complete with statistics. Our measures of swim locomotion utilize a deformable model approach and a novel mathematical analysis of curvature maps that enable even irregular patterns and dynamic changes to be scored without need for thresholding or dropping outlier swimmers from study. Operation of CeleST is mostly automated and only requires minimal investigator interventions, such as the selection of videotaped swim trials and choice of data output format. Data can be analyzed from the level of the single animal to populations of thousands. We document how the CeleST program reveals unexpected preferences for specific swim “gaits” in wild-type C. elegans, uncovers previously unknown mutant phenotypes, efficiently tracks changes in aging populations, and distinguishes “graceful” from poor aging. The sensitivity, dynamic range, and comprehensive nature of CeleST measures elevate swim locomotion analysis to a new level of ease, economy, and detail that enables behavioral plasticity resulting from genetic, cellular, or experience manipulation to be analyzed in ways not previously possible.
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Affiliation(s)
- Christophe Restif
- Center for Computational Biomedicine Imaging and Modeling, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Carolina Ibáñez-Ventoso
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
| | - Mehul M. Vora
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Suzhen Guo
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Dimitris Metaxas
- Center for Computational Biomedicine Imaging and Modeling, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
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10
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Lublin AL, Link CD. Alzheimer's disease drug discovery: in vivo screening using Caenorhabditis elegans as a model for β-amyloid peptide-induced toxicity. DRUG DISCOVERY TODAY. TECHNOLOGIES 2014; 10:e115-e119. [PMID: 24050239 DOI: 10.1016/j.ddtec.2012.02.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is a complex human neurodegenerative disease. Currently the therapeutics for AD only treats the symptoms. While numbers of excellent studies have used mammalian models to discover new compounds, the time and effort involved with screening large numbers of candidates is prohibitive. Cultured mammalian neurons are often used to perform high-throughput screens (HTS); however, cell culture lacks the organismal complexity involved in AD. To address these issues several researchers are turning to the roundworm, Caenorhabditis elegans. C. elegans has numerous models of both Tau and Ab induced toxicity, the two prime components observed to correlate with AD pathology. These models have led to the discovery of numerous AD modulating candidates. Further, the ease of performing RNA interference for any gene in the C. elegans genome allows for identification of proteins involved in the mechanism of drug action. These attributes make C. elegans well positioned to aid in the discovery of new AD therapies.
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Saldanha JN, Parashar A, Pandey S, Powell-Coffman JA. Multiparameter behavioral analyses provide insights to mechanisms of cyanide resistance in Caenorhabditis elegans. Toxicol Sci 2013; 135:156-68. [PMID: 23805000 DOI: 10.1093/toxsci/kft138] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Environmental toxicants influence development, behavior, and ultimately survival. The nematode Caenorhabditis elegans has proven to be an exceptionally powerful model for toxicological studies. Here, we develop novel technologies to describe the effects of cyanide toxicity with high spatiotemporal resolution. Importantly, we use these methods to examine the genetic underpinnings of cyanide resistance. Caenorhabditis elegans that lack the EGL-9 oxygen sensing enzyme have been shown to be resistant to hydrogen cyanide (HCN) gas produced by the pathogen Pseudomonas aeruginosa PAO1. We demonstrate that the cyanide resistance exhibited by egl-9 mutants is completely dependent on the HIF-1 hypoxia-inducible factor and is mediated by the cysl-2 cysteine synthase, which likely functions in metabolic pathways that inactivate cyanide. Further, the expression of cysl-2 correlates with the degree of cyanide resistance exhibited in each genetic background. We find that each mutant exhibits similar relative resistance to HCN gas on plates or to aqueous potassium cyanide in microfluidic chambers. The design of the microfluidic devices, in combination with real-time imaging, addresses a series of challenges presented by mutant phenotypes and by the chemical nature of the toxicant. The microfluidic assay produces a set of behavioral parameters with increased resolution that describe cyanide toxicity and resistance in C. elegans, and this is particularly useful in analyzing subtle phenotypes. These multiparameter analyses of C. elegans behavior hold great potential as a means to monitor the effects of toxicants or chemical interventions in real time and to study the biological networks that underpin toxicant resistance.
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Affiliation(s)
- Jenifer N Saldanha
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
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12
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Antony PMA, Trefois C, Stojanovic A, Baumuratov AS, Kozak K. Light microscopy applications in systems biology: opportunities and challenges. Cell Commun Signal 2013; 11:24. [PMID: 23578051 PMCID: PMC3627909 DOI: 10.1186/1478-811x-11-24] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 03/28/2013] [Indexed: 01/05/2023] Open
Abstract
Biological systems present multiple scales of complexity, ranging from molecules to entire populations. Light microscopy is one of the least invasive techniques used to access information from various biological scales in living cells. The combination of molecular biology and imaging provides a bottom-up tool for direct insight into how molecular processes work on a cellular scale. However, imaging can also be used as a top-down approach to study the behavior of a system without detailed prior knowledge about its underlying molecular mechanisms. In this review, we highlight the recent developments on microscopy-based systems analyses and discuss the complementary opportunities and different challenges with high-content screening and high-throughput imaging. Furthermore, we provide a comprehensive overview of the available platforms that can be used for image analysis, which enable community-driven efforts in the development of image-based systems biology.
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Affiliation(s)
- Paul Michel Aloyse Antony
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Christophe Trefois
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Aleksandar Stojanovic
- Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Luxembourg City, Luxembourg
| | | | - Karol Kozak
- Light Microscopy Centre (LMSC), Institute for Biochemistry, ETH Zurich, Zurich, Switzerland
- Medical Faculty, Technical University Dresden, Dresden, Germany
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Shingai R, Furudate M, Hoshi K, Iwasaki Y. Evaluation of Head Movement Periodicity and Irregularity during Locomotion of Caenorhabditis elegans. Front Behav Neurosci 2013; 7:20. [PMID: 23518645 PMCID: PMC3604732 DOI: 10.3389/fnbeh.2013.00020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 02/28/2013] [Indexed: 11/24/2022] Open
Abstract
Caenorhabditis elegans is suitable for studying the nervous system, which controls behavior. C. elegans shows sinusoidal locomotion on an agar plate. The head moves not only sinusoidally but also more complexly, which reflects regulation of the head muscles by the nervous system. The head movement becomes more irregular with senescence. To date, the head movement complexity has not been quantitatively analyzed. We propose two simple methods for evaluation of the head movement regularity on an agar plate using image analysis. The methods calculate metrics that are a measure of how the head end movement is correlated with body movement. In the first method, the length along the trace of the head end on the agar plate between adjacent intersecting points of the head trace and the quasi-midline of the head trace, which was made by sliding an averaging window of 1/2 the body wavelength, was obtained. Histograms of the lengths showed periodic movement of the head and deviation from it. In the second method, the intersections between the trace of the head end and the trace of the 5 (near the pharynx) or 50% (the mid-body) point from the head end in the centerline length of the worm image were marked. The length of the head trace between adjacent intersections was measured, and a histogram of the lengths was produced. The histogram for the 5% point showed deviation of the head end movement from the movement near the pharynx. The histogram for the 50% point showed deviation of the head movement from the sinusoidal movement of the body center. Application of these methods to wild type and several mutant strains enabled evaluation of their head movement periodicity and irregularity, and revealed a difference in the age-dependence of head movement irregularity between the strains. A set of five parameters obtained from the histograms reliably identifies differences in head movement between strains.
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Affiliation(s)
- Ryuzo Shingai
- Laboratory of Bioscience, Faculty of Engineering, Iwate University Morioka, Iwate, Japan
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14
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Yang J, Chen Z, Yang F, Wang S, Hou F. A microfluidic device for rapid screening of chemotaxis-defective Caenorhabditis elegans mutants. Biomed Microdevices 2012; 15:211-20. [DOI: 10.1007/s10544-012-9719-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Quantification and analysis of ecdysis in the hornworm, Manduca sexta, using machine vision-based tracking. INVERTEBRATE NEUROSCIENCE 2012; 13:45-55. [PMID: 23007685 DOI: 10.1007/s10158-012-0142-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 09/13/2012] [Indexed: 10/27/2022]
Abstract
We have developed a machine vision-based method for automatically tracking deformations in the body wall to monitor ecdysis behaviors in the hornworm, Manduca sexta. The method utilizes naturally occurring features on the animal's body (spiracles) and is highly accurate (>95 % success in tracking). Moreover, it is robust to unanticipated changes in the animal's position and in lighting, and in the event tracking of specific features is lost, tracking can be reestablished within a few cycles without input from the user. We have paired our tracking technique with electromyography and have also compared our in vivo results to fictive motor patterns recorded from isolated nerve cords. We found no major difference in the cycle periods of contractions during naturally occurring ecdysis compared to ecdysis initiated prematurely through injection of the peptide ecdysis-triggering hormone, and we confirmed that the ecdysis period in vivo is statistically similar to that of the fictive motor pattern.
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16
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Forward genetic analysis to identify determinants of dopamine signaling in Caenorhabditis elegans using swimming-induced paralysis. G3-GENES GENOMES GENETICS 2012; 2:961-75. [PMID: 22908044 PMCID: PMC3411251 DOI: 10.1534/g3.112.003533] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 06/23/2012] [Indexed: 11/20/2022]
Abstract
Disrupted dopamine (DA) signaling is believed to contribute to the core features of multiple neuropsychiatric and neurodegenerative disorders. Essential features of DA neurotransmission are conserved in the nematode Caenorhabditis elegans, providing us with an opportunity to implement forward genetic approaches that may reveal novel, in vivo regulators of DA signaling. Previously, we identified a robust phenotype, termed Swimming-induced paralysis (Swip), that emerges in animals deficient in the plasma membrane DA transporter. Here, we report the use and quantitative analysis of Swip in the identification of mutant genes that control DA signaling. Two lines captured in our screen (vt21 and vt22) bear novel dat-1 alleles that disrupt expression and surface trafficking of transporter proteins in vitro and in vivo. Two additional lines, vt25 and vt29, lack transporter mutations but exhibit genetic, biochemical, and behavioral phenotypes consistent with distinct perturbations of DA signaling. Our studies validate the utility of the Swip screen, demonstrate the functional relevance of DA transporter structural elements, and reveal novel genomic loci that encode regulators of DA signaling.
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Lockery SR, Hulme SE, Roberts WM, Robinson KJ, Laromaine A, Lindsay TH, Whitesides GM, Weeks JC. A microfluidic device for whole-animal drug screening using electrophysiological measures in the nematode C. elegans. LAB ON A CHIP 2012; 12:2211-20. [PMID: 22588281 PMCID: PMC3372093 DOI: 10.1039/c2lc00001f] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This paper describes the fabrication and use of a microfluidic device for performing whole-animal chemical screens using non-invasive electrophysiological readouts of neuromuscular function in the nematode worm, C. elegans. The device consists of an array of microchannels to which electrodes are attached to form recording modules capable of detecting the electrical activity of the pharynx, a heart-like neuromuscular organ involved in feeding. The array is coupled to a tree-like arrangement of distribution channels that automatically delivers one nematode to each recording module. The same channels are then used to perfuse the recording modules with test solutions while recording the electropharyngeogram (EPG) from each worm with sufficient sensitivity to detect each pharyngeal contraction. The device accurately reported the acute effects of known anthelmintics (anti-nematode drugs) and also correctly distinguished a specific drug-resistant mutant strain of C. elegans from wild type. The approach described here is readily adaptable to parasitic species for the identification of novel anthelmintics. It is also applicable in toxicology and drug discovery programs for human metabolic and degenerative diseases for which C. elegans is used as a model.
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Affiliation(s)
- Shawn R Lockery
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403-1254, USA.
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18
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Wählby C, Kamentsky L, Liu ZH, Riklin-Raviv T, Conery AL, O'Rourke EJ, Sokolnicki KL, Visvikis O, Ljosa V, Irazoqui JE, Golland P, Ruvkun G, Ausubel FM, Carpenter AE. An image analysis toolbox for high-throughput C. elegans assays. Nat Methods 2012; 9:714-6. [PMID: 22522656 PMCID: PMC3433711 DOI: 10.1038/nmeth.1984] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 02/07/2012] [Indexed: 11/08/2022]
Abstract
We present a toolbox for high-throughput screening of image-based Caenorhabditis elegans phenotypes. The image analysis algorithms measure morphological phenotypes in individual worms and are effective for a variety of assays and imaging systems. This WormToolbox is available through the open-source CellProfiler project and enables objective scoring of whole-worm high-throughput image-based assays of C. elegans for the study of diverse biological pathways that are relevant to human disease.
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Affiliation(s)
- Carolina Wählby
- Imaging Platform, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts, USA.
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19
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Zheng M, Gorelenkova O, Yang J, Feng Z. A liquid phase based C. elegans behavioral analysis system identifies motor activity loss in a nematode Parkinson's disease model. J Neurosci Methods 2012; 204:234-7. [PMID: 22108336 DOI: 10.1016/j.jneumeth.2011.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 11/01/2011] [Accepted: 11/09/2011] [Indexed: 11/20/2022]
Abstract
Motor activity of Caenorhabditis elegans is widely used to study the mechanisms ranging from basic neuronal functions to human neurodegenerative diseases. It may also serve as a paradigm to screen for potential therapeutic reagents treating these diseases. Here, we developed an automated, 96-well plate and liquid phase based system that quantifies nematode motor activity in real time. Using this system, we identified an adult-onset, ageing-associated motor activity loss in a transgenic nematode line expressing human pathogenic G2019S mutant LRRK2 (leucine-rich repeat kinase 2), the leading genetic cause of Parkinson's disease characterized by dopaminergic neurodegeneration associated motor deficient mainly in elder citizens. Thus, our system may be used as a platform to screen for potential therapeutic drugs treating Parkinson's disease. It can also be used to monitor motor activity of nematodes in liquid phase at similar scenario.
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Affiliation(s)
- Maohua Zheng
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, United States
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20
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Vogelstein JT, Vogelstein RJ, Priebe CE. Are mental properties supervenient on brain properties? Sci Rep 2011; 1:100. [PMID: 22355618 PMCID: PMC3216585 DOI: 10.1038/srep00100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 09/01/2011] [Indexed: 12/01/2022] Open
Abstract
The "mind-brain supervenience" conjecture suggests that all mental properties are derived from the physical properties of the brain. To address the question of whether the mind supervenes on the brain, we frame a supervenience hypothesis in rigorous statistical terms. Specifically, we propose a modified version of supervenience (called ε-supervenience) that is amenable to experimental investigation and statistical analysis. To illustrate this approach, we perform a thought experiment that illustrates how the probabilistic theory of pattern recognition can be used to make a one-sided determination of ε-supervenience. The physical property of the brain employed in this analysis is the graph describing brain connectivity (i.e., the brain-graph or connectome). ε-supervenience allows us to determine whether a particular mental property can be inferred from one's connectome to within any given positive misclassification rate, regardless of the relationship between the two. This may provide further motivation for cross-disciplinary research between neuroscientists and statisticians.
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Affiliation(s)
- Joshua T Vogelstein
- Department of Applied Mathematics & Statistics, Johns Hopkins University, Baltimore, MD, USA.
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21
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Yanik MF, Rohde CB, Pardo-Martin C. Technologies for Micromanipulating, Imaging, and Phenotyping Small Invertebrates and Vertebrates. Annu Rev Biomed Eng 2011; 13:185-217. [DOI: 10.1146/annurev-bioeng-071910-124703] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mehmet Fatih Yanik
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Christopher B. Rohde
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Carlos Pardo-Martin
- Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139;
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
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22
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Temmerman L, Meelkop E, Janssen T, Bogaerts A, Lindemans M, Husson SJ, Beets I, Schoofs L. C. elegans homologs of insect clock proteins: a tale of many stories. Ann N Y Acad Sci 2011; 1220:137-48. [PMID: 21388411 DOI: 10.1111/j.1749-6632.2010.05927.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
As a consequence of the Earth's axial rotation, organisms display daily recurring rhythms in behavior and biochemical properties, such as hormone titers. The neuronal system controlling such changes is best studied in the fruit fly Drosophila melanogaster. In the nematode worm Caenorhabditis elegans, most homologs of these genes function in the heterochronic pathway controlling the (timing of) developmental events. Recent data indicate that in the worm at least one of the genes involved in developmental timing is also active in circadian rhythm control, thereby opening up new perspectives on a central (neuronal) timer interfering with many processes. Also, new neuropeptidergic clock homologs have been identified in nematodes, supporting the idea of a broad range of clock-regulated targets. We will describe the current knowledge on homologous clock genes in C. elegans with a focus on the recently discovered pigment dispersing factor gene homologs. Similarities between developmental and daily timing are discussed.
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Affiliation(s)
- Liesbet Temmerman
- Research Group of Functional Genomics and Proteomics, K.U. Leuven, Leuven, Belgium
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23
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Sleigh JN, Buckingham SD, Esmaeili B, Viswanathan M, Cuppen E, Westlund BM, Sattelle DB. A novel Caenorhabditis elegans allele, smn-1(cb131), mimicking a mild form of spinal muscular atrophy, provides a convenient drug screening platform highlighting new and pre-approved compounds. Hum Mol Genet 2010; 20:245-60. [PMID: 20962036 DOI: 10.1093/hmg/ddq459] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Spinal muscular atrophy (SMA), an autosomal recessive genetic disorder, is characterized by the selective degeneration of lower motor neurons, leading to muscle atrophy and, in the most severe cases, paralysis and death. Deletions and point mutations cause reduced levels of the widely expressed survival motor neuron (SMN) protein, which has been implicated in a range of cellular processes. The mechanisms underlying disease pathogenesis are unclear, and there is no effective treatment. Several animal models have been developed to study SMN function including the nematode, Caenorhabditis elegans, in which a large deletion in the gene homologous to SMN, smn-1, results in neuromuscular dysfunction and larval lethality. Although useful, this null mutant, smn-1(ok355), is not well suited to drug screening. We report the isolation and characterization of smn-1(cb131), a novel allele encoding a substitution in a highly conserved residue of exon 2, resembling a point mutation found in a patient with type IIIb SMA. The smn-1(cb131) animals display milder yet similar defects when compared with the smn-1 null mutant. Using an automated phenotyping system, mutants were shown to swim slower than wild-type animals. This phenotype was used to screen a library of 1040 chemical compounds for drugs that ameliorate the defect, highlighting six for subsequent testing. 4-aminopyridine, gaboxadol hydrochloride and N-acetylneuraminic acid all rescued at least one aspect of smn-1 phenotypic dysfunction. These findings may assist in accelerating the development of drugs for the treatment of SMA.
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Affiliation(s)
- James N Sleigh
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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24
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Sznitman R, Gupta M, Hager GD, Arratia PE, Sznitman J. Multi-environment model estimation for motility analysis of Caenorhabditis elegans. PLoS One 2010; 5:e11631. [PMID: 20661478 PMCID: PMC2908547 DOI: 10.1371/journal.pone.0011631] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 06/23/2010] [Indexed: 11/30/2022] Open
Abstract
The nematode Caenorhabditis elegans is a well-known model organism used to investigate fundamental questions in biology. Motility assays of this small roundworm are designed to study the relationships between genes and behavior. Commonly, motility analysis is used to classify nematode movements and characterize them quantitatively. Over the past years, C. elegans' motility has been studied across a wide range of environments, including crawling on substrates, swimming in fluids, and locomoting through microfluidic substrates. However, each environment often requires customized image processing tools relying on heuristic parameter tuning. In the present study, we propose a novel Multi-Environment Model Estimation (MEME) framework for automated image segmentation that is versatile across various environments. The MEME platform is constructed around the concept of Mixture of Gaussian (MOG) models, where statistical models for both the background environment and the nematode appearance are explicitly learned and used to accurately segment a target nematode. Our method is designed to simplify the burden often imposed on users; here, only a single image which includes a nematode in its environment must be provided for model learning. In addition, our platform enables the extraction of nematode ‘skeletons’ for straightforward motility quantification. We test our algorithm on various locomotive environments and compare performances with an intensity-based thresholding method. Overall, MEME outperforms the threshold-based approach for the overwhelming majority of cases examined. Ultimately, MEME provides researchers with an attractive platform for C. elegans' segmentation and ‘skeletonizing’ across a wide range of motility assays.
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Affiliation(s)
- Raphael Sznitman
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Manaswi Gupta
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Gregory D. Hager
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Paulo E. Arratia
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Josué Sznitman
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
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25
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Abstract
Current high-throughput screening methods for drug discovery rely on the existence of targets. Moreover, most of the hits generated during screenings turn out to be invalid after further testing in animal models. To by-pass these limitations, efforts are now being made to screen chemical libraries on whole animals. One of the most commonly used animal model in biology is the murine model Mus musculus. However, its cost limit its use in large-scale therapeutic screening. In contrast, the nematode Caenorhabditis elegans, the fruit fly Drosophila melanogaster, and the fish Danio rerio are gaining momentum as screening tools. These organisms combine genetic amenability, low cost and culture conditions that are compatible with large-scale screens. Their main advantage is to allow high-throughput screening in a whole-animal context. Moreover, their use is not dependent on the prior identification of a target and permits the selection of compounds with an improved safety profile. This review surveys the versatility of these animal models for drug discovery and discuss the options available at this day.
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Abstract
AbstractThe nematode Caenorhabditis elegans is a genetic model organism and the only animal with a complete nervous system wiring diagram. With only 302 neurons and 95 striated muscle cells, a rich array of mutants with defective locomotion and the facility for individual targeted gene knockdown by RNA interference, it lends itself to the exploration of gene function at nerve muscle junctions. With approximately 60% of human disease genes having a C. elegans homologue, there is growing interest in the deployment of lowcost, high-throughput, drug screens of nematode transgenic and mutant strains mimicking aspects of the pathology of devastating human neuromuscular disorders. Here we explore the contributions already made by C. elegans to our understanding of muscular dystrophies (Duchenne and Becker), spinal muscular atrophy, amyotrophic lateral sclerosis, Friedreich’s ataxia, inclusion body myositis and the prospects for contributions to other neuromuscular disorders. A bottleneck to low-cost, in vivo, large-scale chemical library screening for new candidate therapies has been rapid, automated, behavioural phenotyping. Recent progress in quantifying simple swimming (thrashing) movements is making such screening possible and is expediting the translation of drug candidates towards the clinic.
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Dillon J, Andrianakis I, Bull K, Glautier S, O'Connor V, Holden-Dye L, James C. AutoEPG: software for the analysis of electrical activity in the microcircuit underpinning feeding behaviour of Caenorhabditis elegans. PLoS One 2009; 4:e8482. [PMID: 20041123 PMCID: PMC2795780 DOI: 10.1371/journal.pone.0008482] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 11/09/2009] [Indexed: 11/19/2022] Open
Abstract
Background The pharyngeal microcircuit of the nematode Caenorhabditis elegans serves as a model for analysing neural network activity and is amenable to electrophysiological recording techniques. One such technique is the electropharyngeogram (EPG) which has provided insight into the genetic basis of feeding behaviour, neurotransmission and muscle excitability. However, the detailed manual analysis of the digital recordings necessary to identify subtle differences in activity that reflect modulatory changes within the underlying network is time consuming and low throughput. To address this we have developed an automated system for the high-throughput and discrete analysis of EPG recordings (AutoEPG). Methodology/Principal Findings AutoEPG employs a tailor made signal processing algorithm that automatically detects different features of the EPG signal including those that report on the relaxation and contraction of the muscle and neuronal activity. Manual verification of the detection algorithm has demonstrated AutoEPG is capable of very high levels of accuracy. We have further validated the software by analysing existing mutant strains with known pharyngeal phenotypes detectable by the EPG. In doing so, we have more precisely defined an evolutionarily conserved role for the calcium-dependent potassium channel, SLO-1, in modulating the rhythmic activity of neural networks. Conclusions/Significance AutoEPG enables the consistent analysis of EPG recordings, significantly increases analysis throughput and allows the robust identification of subtle changes in the electrical activity of the pharyngeal nervous system. It is anticipated that AutoEPG will further add to the experimental tractability of the C. elegans pharynx as a model neural circuit.
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Affiliation(s)
- James Dillon
- School of Biological Sciences, Bassett Crescent East, University of Southampton, Southampton, United Kingdom.
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28
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Timing of locomotor activity circadian rhythms in Caenorhabditis elegans. PLoS One 2009; 4:e7571. [PMID: 19859568 PMCID: PMC2764868 DOI: 10.1371/journal.pone.0007571] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 10/01/2009] [Indexed: 11/19/2022] Open
Abstract
Circadian rhythms are driven by endogenous biological clocks and are synchronized to environmental cues. The chronobiological study of Caenorhabditis elegans, an extensively used animal model for developmental and genetic research, might provide fundamental information about the basis of circadian rhythmicity in eukaryotes, due to its ease of use and manipulations, as well as availability of genetic data and mutant strains. The aim of this study is to fully characterize the circadian rhythm of locomotor activity in C. elegans, as well as a means for genetic screening in this nematode and the identification of circadian mutants. We have developed an infrared method to measure locomotor activity in C. elegans and found that, under constant conditions, although inter-individual variability is present, circadian periodicity shows a population distribution of periods centered at 23.9±0.4 h and is temperature-compensated. Locomotor activity is entrainable by light-dark cycles and by low-amplitude temperature cycles, peaking around the night-day transition and day, respectively. In addition, lin-42(mg152) or lin-42(n1089) mutants (bearing a mutation in the lin-42 gene, homolog to the per gene) exhibit a significantly longer circadian period of 25.2±0.4 h or 25.6±0.5 h, respectively. Our results represent a complete description of the locomotor activity rhythm in C. elegans, with a methodology that allowed us to uncover three of the key features of circadian systems: entrainment, free-running and temperature compensation. In addition, abnormal circadian periods in clock mutants suggest a common molecular machinery responsible for circadian rhythmicity. Our analysis of circadian rhythmicity in C. elegans opens the possibility for further screening for circadian mutations in this species.
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29
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Buckingham SD, Sattelle DB. Fast, automated measurement of nematode swimming (thrashing) without morphometry. BMC Neurosci 2009; 10:84. [PMID: 19619274 PMCID: PMC2729753 DOI: 10.1186/1471-2202-10-84] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 07/20/2009] [Indexed: 11/18/2022] Open
Abstract
Background The "thrashing assay", in which nematodes are placed in liquid and the frequency of lateral swimming ("thrashing") movements estimated, is a well-established method for measuring motility in the genetic model organism Caenorhabditis elegans as well as in parasitic nematodes. It is used as an index of the effects of drugs, chemicals or mutations on motility and has proved useful in identifying mutants affecting behaviour. However, the method is laborious, subject to experimenter error, and therefore does not permit high-throughput applications. Existing automation methods usually involve analysis of worm shape, but this is computationally demanding and error-prone. Here we present a novel, robust and rapid method of automatically counting the thrashing frequency of worms that avoids morphometry but nonetheless gives a direct measure of thrashing frequency. Our method uses principal components analysis to remove the background, followed by computation of a covariance matrix of the remaining image frames from which the interval between statistically-similar frames is estimated. Results We tested the performance of our covariance method in measuring thrashing rates of worms using mutations that affect motility and found that it accurately substituted for laborious, manual measurements over a wide range of thrashing rates. The algorithm used also enabled us to determine a dose-dependent inhibition of thrashing frequency by the anthelmintic drug, levamisole, illustrating the suitability of the system for assaying the effects of drugs and chemicals on motility. Furthermore, the algorithm successfully measured the actions of levamisole on a parasitic nematode, Haemonchus contortus, which undergoes complex contorted shapes whilst swimming, without alterations in the code or of any parameters, indicating that it is applicable to different nematode species, including parasitic nematodes. Our method is capable of analyzing a 30 s movie in less than 30 s and can therefore be deployed in rapid screens. Conclusion We demonstrate that a covariance-based method yields a fast, reliable, automated measurement of C. elegans motility which can replace the far more time-consuming, manual method. The absence of a morphometry step means that the method can be applied to any nematode that swims in liquid and, together with its speed, this simplicity lends itself to deployment in large-scale chemical and genetic screens.
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Affiliation(s)
- Steven D Buckingham
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK.
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