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Wang Z. Caenorhabditis elegans as an In Vivo Model Organism to Elucidate Teratogenic Effects. Methods Mol Biol 2024; 2753:283-306. [PMID: 38285345 DOI: 10.1007/978-1-0716-3625-1_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
Exogenous teratogens contribute to approximately 10% of the human abnormality with exposure occurrence during the prenatal and fetal period. However, the assessment methods and underlying mechanism remain unclear. The nematode Caenorhabditis elegans has been recognized as one of the ideal model animals for toxicologic research as convenient culture, low cost, and complete phenotypes and genomic profiling. This chapter describes the protocols about the estimations on the teratogenic effects using nematodes as model organisms, including the growth, development, behavior, reproduction, energy balance, and transgenes.
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Affiliation(s)
- Zhenglu Wang
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China
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2
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Kamal M, Tokmakjian L, Knox J, Han D, Moshiri H, Magomedova L, Nguyen KCQ, Zheng H, Burns AR, Cooke B, Lacoste J, Yeo M, Hall DH, Cummins CL, Roy PJ. PGP-14 establishes a polar lipid permeability barrier within the C. elegans pharyngeal cuticle. PLoS Genet 2023; 19:e1011008. [PMID: 37930961 PMCID: PMC10653525 DOI: 10.1371/journal.pgen.1011008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 11/16/2023] [Accepted: 10/05/2023] [Indexed: 11/08/2023] Open
Abstract
The cuticles of ecdysozoan animals are barriers to material loss and xenobiotic insult. Key to this barrier is lipid content, the establishment of which is poorly understood. Here, we show that the p-glycoprotein PGP-14 functions coincidently with the sphingomyelin synthase SMS-5 to establish a polar lipid barrier within the pharyngeal cuticle of the nematode C. elegans. We show that PGP-14 and SMS-5 are coincidentally expressed in the epithelium that surrounds the anterior pharyngeal cuticle where PGP-14 localizes to the apical membrane. pgp-14 and sms-5 also peak in expression at the time of new cuticle synthesis. Loss of PGP-14 and SMS-5 dramatically reduces pharyngeal cuticle staining by Nile Red, a key marker of polar lipids, and coincidently alters the nematode's response to a wide-range of xenobiotics. We infer that PGP-14 exports polar lipids into the developing pharyngeal cuticle in an SMS-5-dependent manner to safeguard the nematode from environmental insult.
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Affiliation(s)
- Muntasir Kamal
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Levon Tokmakjian
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Jessica Knox
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Duhyun Han
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Houtan Moshiri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Lilia Magomedova
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Ken CQ Nguyen
- Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Hong Zheng
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Andrew R. Burns
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Brittany Cooke
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Jessica Lacoste
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - May Yeo
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - David H. Hall
- Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Carolyn L. Cummins
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Peter J. Roy
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
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3
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Bonnard E, Liu J, Zjacic N, Alvarez L, Scholz M. Automatically tracking feeding behavior in populations of foraging C. elegans. eLife 2022; 11:e77252. [PMID: 36083280 PMCID: PMC9462848 DOI: 10.7554/elife.77252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Caenorhabditis elegans feeds on bacteria and other small microorganisms which it ingests using its pharynx, a neuromuscular pump. Currently, measuring feeding behavior requires tracking a single animal, indirectly estimating food intake from population-level metrics, or using restrained animals. To enable large throughput feeding measurements of unrestrained, crawling worms on agarose plates at a single worm resolution, we developed an imaging protocol and a complementary image analysis tool called PharaGlow. We image up to 50 unrestrained crawling worms simultaneously and extract locomotion and feeding behaviors. We demonstrate the tool's robustness and high-throughput capabilities by measuring feeding in different use-case scenarios, such as through development, with genetic and chemical perturbations that result in faster and slower pumping, and in the presence or absence of food. Finally, we demonstrate that our tool is capable of long-term imaging by showing behavioral dynamics of mating animals and worms with different genetic backgrounds. The low-resolution fluorescence microscopes required are readily available in C. elegans laboratories, and in combination with our python-based analysis workflow makes this methodology easily accessible. PharaGlow therefore enables the observation and analysis of the temporal dynamics of feeding and locomotory behaviors with high-throughput and precision in a user-friendly system.
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Affiliation(s)
- Elsa Bonnard
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Jun Liu
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Nicolina Zjacic
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
- Institute of Medical Genetics, University of ZurichZurichSwitzerland
| | - Luis Alvarez
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Monika Scholz
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
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4
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Katz SS, Barker TJ, Maul-Newby HM, Sparacio AP, Nguyen KCQ, Maybrun CL, Belfi A, Cohen JD, Hall DH, Sundaram MV, Frand AR. A transient apical extracellular matrix relays cytoskeletal patterns to shape permanent acellular ridges on the surface of adult C. elegans. PLoS Genet 2022; 18:e1010348. [PMID: 35960773 PMCID: PMC9401183 DOI: 10.1371/journal.pgen.1010348] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 08/24/2022] [Accepted: 07/18/2022] [Indexed: 11/19/2022] Open
Abstract
Epithelial cells secrete apical extracellular matrices to form protruding structures such as denticles, ridges, scales, or teeth. The mechanisms that shape these structures remain poorly understood. Here, we show how the actin cytoskeleton and a provisional matrix work together to sculpt acellular longitudinal alae ridges in the cuticle of adult C. elegans. Transient assembly of longitudinal actomyosin filaments in the underlying lateral epidermis accompanies deposition of the provisional matrix at the earliest stages of alae formation. Actin is required to pattern the provisional matrix into longitudinal bands that are initially offset from the pattern of longitudinal actin filaments. These bands appear ultrastructurally as alternating regions of adhesion and separation within laminated provisional matrix layers. The provisional matrix is required to establish these demarcated zones of adhesion and separation, which ultimately give rise to alae ridges and their intervening valleys, respectively. Provisional matrix proteins shape the alae ridges and valleys but are not present within the final structure. We propose a morphogenetic mechanism wherein cortical actin patterns are relayed to the laminated provisional matrix to set up distinct zones of matrix layer separation and accretion that shape a permanent and acellular matrix structure.
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Affiliation(s)
- Sophie S. Katz
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Trevor J. Barker
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Hannah M. Maul-Newby
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Alessandro P. Sparacio
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Ken C. Q. Nguyen
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Chloe L. Maybrun
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Alexandra Belfi
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Jennifer D. Cohen
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - David H. Hall
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Meera V. Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Alison R. Frand
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
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5
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Stojanovski K, Großhans H, Towbin BD. Coupling of growth rate and developmental tempo reduces body size heterogeneity in C. elegans. Nat Commun 2022; 13:3132. [PMID: 35668054 PMCID: PMC9170734 DOI: 10.1038/s41467-022-29720-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 03/24/2022] [Indexed: 11/15/2022] Open
Abstract
Animals increase by orders of magnitude in volume during development. Therefore, small variations in growth rates among individuals could amplify to a large heterogeneity in size. By live imaging of C. elegans, we show that amplification of size heterogeneity is prevented by an inverse coupling of the volume growth rate to the duration of larval stages and does not involve strict size thresholds for larval moulting. We perturb this coupling by changing the developmental tempo through manipulation of a transcriptional oscillator that controls the duration of larval development. As predicted by a mathematical model, this perturbation alters the body volume. Model analysis shows that an inverse relation between the period length and the growth rate is an intrinsic property of genetic oscillators and can occur independently of additional complex regulation. This property of genetic oscillators suggests a parsimonious mechanism that counteracts the amplification of size differences among individuals during development. Animals must reach the correct size during development, despite stochastic differences in their growth rate. Here, Stojanovski et al. show that a coupling of growth and development by an oscillatory timer buffers fluctuations in the growth of the nematode C. elegans to ensure its correct size.
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Affiliation(s)
| | - Helge Großhans
- Friedrich Miescher Institute for Biomedical Research (FMI), Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Benjamin D Towbin
- University of Bern, Bern, Switzerland. .,Friedrich Miescher Institute for Biomedical Research (FMI), Basel, Switzerland.
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6
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Changes in body shape implicate cuticle stretch in C. elegans growth control. Cells Dev 2022; 170:203780. [DOI: 10.1016/j.cdev.2022.203780] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/21/2022] [Accepted: 04/12/2022] [Indexed: 11/23/2022]
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7
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Cohen JD, Sundaram MV. C. elegans Apical Extracellular Matrices Shape Epithelia. J Dev Biol 2020; 8:E23. [PMID: 33036165 PMCID: PMC7712855 DOI: 10.3390/jdb8040023] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 02/07/2023] Open
Abstract
Apical extracellular matrices (aECMs) coat exposed surfaces of epithelia to shape developing tissues and protect them from environmental insults. Despite their widespread importance for human health, aECMs are poorly understood compared to basal and stromal ECMs. The nematode Caenorhabditis elegans contains a variety of distinct aECMs, some of which share many of the same types of components (lipids, lipoproteins, collagens, zona pellucida domain proteins, chondroitin glycosaminoglycans and proteoglycans) with mammalian aECMs. These aECMs include the eggshell, a glycocalyx-like pre-cuticle, both collagenous and chitin-based cuticles, and other understudied aECMs of internal epithelia. C. elegans allows rapid genetic manipulations and live imaging of fluorescently-tagged aECM components, and is therefore providing new insights into aECM structure, trafficking, assembly, and functions in tissue shaping.
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Affiliation(s)
| | - Meera V. Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine 415 Curie Blvd, Philadelphia, PA 19104-6145, USA;
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8
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Teething during sleep: Ultrastructural analysis of pharyngeal muscle and cuticular grinder during the molt in Caenorhabditis elegans. PLoS One 2020; 15:e0233059. [PMID: 32433687 PMCID: PMC7239488 DOI: 10.1371/journal.pone.0233059] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/27/2020] [Indexed: 11/26/2022] Open
Abstract
Complex extracellular structures exist throughout phylogeny, but the dynamics of their formation and dissolution are often opaque. One example is the pharyngeal grinder of the nematode Caenorhabditis elegans, an extracellular structure that ruptures bacteria during feeding. During each larval transition stage, called lethargus, the grinder is replaced with one of a larger size. Here, we characterize at the ultrastructural level the deconstruction of the larval grinder and the construction of the adult grinder during the fourth larval stage (L4)-to-adult transition. Early in L4 lethargus, pharyngeal muscle cells trans-differentiate from contractile to secretory cells, as evidenced by the appearance of clear and dense core vesicles and disruptions in sarcomere organization. This is followed, within minutes, by the dissolution of the L4 grinder and the formation and maturation of the adult grinder. Components of the nascent adult grinder are deposited basally, and are separated from the dissolving larval grinder by a visible apical layer. The complete grinder is a lamellated extracellular matrix comprised of five layers. Following grinder formation, pharyngeal muscle cells regain ultrastructural contractile properties, and muscle contractions resume. Our findings add to our understanding of how complex extracellular structures assemble and dissemble.
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9
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Fan J, Ji T, Wang K, Huang J, Wang M, Manning L, Dong X, Shi Y, Zhang X, Shao Z, Colón-Ramos DA. A muscle-epidermis-glia signaling axis sustains synaptic specificity during allometric growth in Caenorhabditis elegans. eLife 2020; 9:55890. [PMID: 32255430 PMCID: PMC7164957 DOI: 10.7554/elife.55890] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/05/2020] [Indexed: 02/06/2023] Open
Abstract
Synaptic positions underlie precise circuit connectivity. Synaptic positions can be established during embryogenesis and sustained during growth. The mechanisms that sustain synaptic specificity during allometric growth are largely unknown. We performed forward genetic screens in C. elegans for regulators of this process and identified mig-17, a conserved ADAMTS metalloprotease. Proteomic mass spectrometry, cell biological and genetic studies demonstrate that MIG-17 is secreted from cells like muscles to regulate basement membrane proteins. In the nematode brain, the basement membrane does not directly contact synapses. Instead, muscle-derived basement membrane coats one side of the glia, while glia contact synapses on their other side. MIG-17 modifies the muscle-derived basement membrane to modulate epidermal-glial crosstalk and sustain glia location and morphology during growth. Glia position in turn sustains the synaptic pattern established during embryogenesis. Our findings uncover a muscle-epidermis-glia signaling axis that sustains synaptic specificity during the organism's allometric growth.
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Affiliation(s)
- Jiale Fan
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Tingting Ji
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Kai Wang
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Jichang Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Mengqing Wang
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Laura Manning
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Xiaohua Dong
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Yanjun Shi
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Xumin Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Zhiyong Shao
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Daniel A Colón-Ramos
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,Instituto de Neurobiología, Recinto de Ciencias Médicas, Universidad de Puerto Rico, San Juan, Puerto Rico
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10
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Abete-Luzi P, Fukushige T, Yun S, Krause MW, Eisenmann DM. New Roles for the Heterochronic Transcription Factor LIN-29 in Cuticle Maintenance and Lipid Metabolism at the Larval-to-Adult Transition in Caenorhabditis elegans. Genetics 2020; 214:669-690. [PMID: 31974205 PMCID: PMC7054012 DOI: 10.1534/genetics.119.302860] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/21/2020] [Indexed: 11/18/2022] Open
Abstract
Temporal regulation of gene expression is a crucial aspect of metazoan development. In the roundworm Caenorhabditis elegans, the heterochronic pathway controls multiple developmental events in a time-specific manner. The most downstream effector of this pathway, the zinc-finger transcription factor LIN-29, acts in the last larval stage (L4) to regulate elements of the larval-to-adult switch. Here, we explore new LIN-29 targets and their implications for this developmental transition. We used RNA-sequencing to identify genes differentially expressed between animals misexpressing LIN-29 at an early time point and control animals. Among 230 LIN-29-activated genes, we found that genes encoding cuticle collagens were overrepresented. Interestingly, expression of lin-29 and some of these collagens was increased in adults with cuticle damage, suggesting a previously unknown function for LIN-29 in adult cuticle maintenance. On the other hand, genes involved in fat metabolism were enriched among 350 LIN-29-downregulated targets. We used mass spectrometry to assay lipid content in animals overexpressing LIN-29 and observed reduced fatty acid levels. Many LIN-29-repressed genes are normally expressed in the intestine, suggesting cell-nonautonomous regulation. We identified several LIN-29 upregulated genes encoding signaling molecules that may act as mediators in the regulation of intestinally expressed genes encoding fat metabolic enzymes and vitellogenins. Overall, our results support the model of LIN-29 as a major regulator of adult cuticle synthesis and integrity, and as the trigger for metabolic changes that take place at the important transition from rapid growth during larval life to slower growth and offspring production during adulthood.
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Affiliation(s)
- Patricia Abete-Luzi
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland 21250
| | - Tetsunari Fukushige
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Sijung Yun
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Michael W Krause
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - David M Eisenmann
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland 21250
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11
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Bornhorst J, Ebert F, Meyer S, Ziemann V, Xiong C, Guttenberger N, Raab A, Baesler J, Aschner M, Feldmann J, Francesconi K, Raber G, Schwerdtle T. Toxicity of three types of arsenolipids: species-specific effects inCaenorhabditis elegans. Metallomics 2020; 12:794-798. [DOI: 10.1039/d0mt00039f] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
AsHCs and AsTAG are highly bioavailable toC. elegans., AsHCs are metabolized byC. elegans., AsHCs but not AsTAG and AsFA affect survival and development inC. elegans.
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12
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Shinn-Thomas JH, Scanga SE, Spica PS, Nariya HK, Klempic E, Brockett MR. Wrapping culture plates with Parafilm M ® increases Caenorhabditis elegans growth. BMC Res Notes 2019; 12:818. [PMID: 31856898 PMCID: PMC6924044 DOI: 10.1186/s13104-019-4854-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 12/11/2019] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVE Parafilm M® is a moisture-resistant thermoplastic commonly used to seal Nematode Growth Media (NGM) agar plates on which the nematode Caenorhabditis elegans is cultured. This practice reduces media dehydration and microbial contamination. However, the effects on C. elegans individuals of placing this barrier between the external environment and the interior of the NGM plate are currently unknown. Our research aims to determine if this common practice engenders developmental changes, such as growth, that could subsequently and unintentionally alter experimental data. We compared the larval growth over 48 h of animals cultured on Parafilm-wrapped and unwrapped control NGM plates. RESULTS Wrapping culture plates with Parafilm significantly accelerated and increased larval growth, with a 0.87 μm/h increase in growth rate (~ 6%) and a 37.90 μm increase in the change in growth (Δgrowth; ~ 5%) over 48 h. Therefore, C. elegans investigators should be aware that wrapping their experimental cultures with Parafilm may result in statistically detectable changes in worm growth and possibly other developmental processes.
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Affiliation(s)
| | - Sara E. Scanga
- Department of Biology, Utica College, 1600 Burrstone Road, Utica, NY 13502 USA
| | - Patrick S. Spica
- Department of Biology, Utica College, 1600 Burrstone Road, Utica, NY 13502 USA
| | - Hardik K. Nariya
- Department of Biology, Utica College, 1600 Burrstone Road, Utica, NY 13502 USA
| | - Emra Klempic
- Department of Biology, Utica College, 1600 Burrstone Road, Utica, NY 13502 USA
- Division of Cardiac Surgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642 USA
| | - Mary R. Brockett
- Department of Biology, Utica College, 1600 Burrstone Road, Utica, NY 13502 USA
- Department of Microbiology and Immunology, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
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13
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Ravi B, Garcia J, Collins K. The HSN egg-laying command neurons regulate the defecation motor program in Caenorhabditis elegans: Integration. MICROPUBLICATION BIOLOGY 2019; 2019. [PMID: 32550458 PMCID: PMC7252377 DOI: 10.17912/micropub.biology.000095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Bhavya Ravi
- Neuroscience Program, Miller School of Medicine, University of Miami, Miami, FL 33136.,Present address: Department of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Jessica Garcia
- Department of Biology, University of Miami, Coral Gables, FL 33146
| | - Kevin Collins
- Neuroscience Program, Miller School of Medicine, University of Miami, Miami, FL 33136.,Department of Biology, University of Miami, Coral Gables, FL 33146
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14
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Woodruff GC, Willis JH, Phillips PC. Dramatic evolution of body length due to postembryonic changes in cell size in a newly discovered close relative of Caenorhabditis elegans. Evol Lett 2018; 2:427-441. [PMID: 30283693 PMCID: PMC6121821 DOI: 10.1002/evl3.67] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 06/08/2018] [Accepted: 06/11/2018] [Indexed: 12/24/2022] Open
Abstract
Understanding morphological diversity-and morphological constraint-has been a central question in evolutionary biology since its inception. Nematodes of the genus Caenorhabditis, which contains the well-studied model organism C. elegans, display remarkable morphological consistency in the face of extensive genetic divergence. Here, we provide a description of the broad developmental patterns of a newly discovered species, C. sp. 34, which was isolated from fresh figs in Okinawa and which is among the closest known relatives of C. elegans. C. sp. 34 displays an extremely large body size; it can grow to be nearly twice as long as C. elegans and all other known members of the genus. Observations of the timing of developmental milestones reveal that C. sp. 34 develops about twice as slowly as C. elegans. Measurements of embryonic and larval size show that the size difference between C. sp. 34 and C. elegans is largely due to postembryonic events, particularly during the transition from larval to adult stages. This difference in size is not attributable to differences in germ line chromosome number or the number of somatic cells. The overall difference in body size is therefore largely attributable to changes in cell size via increased cytoplasmic volume. Because of its close relationship to C. elegans, the distinctness of C. sp. 34 provides an ideal system for the detailed analysis of evolutionary diversification. The context of over 40 years of C. elegans developmental genetics also reveals clues into how natural selection and developmental constraint act jointly to promote patterns of morphological stasis and divergence in this group.
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Affiliation(s)
- Gavin C. Woodruff
- Forestry and Forest Products Research InstituteForest Pathology LaboratoryTsukubaJapan
- Department of Biology, Institute of Ecology and EvolutionUniversity of OregonEugeneOregon97403
| | - John H. Willis
- Department of Biology, Institute of Ecology and EvolutionUniversity of OregonEugeneOregon97403
| | - Patrick C. Phillips
- Department of Biology, Institute of Ecology and EvolutionUniversity of OregonEugeneOregon97403
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15
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Lecomte-Pradines C, Hertel-Aas T, Coutris C, Gilbin R, Oughton D, Alonzo F. A dynamic energy-based model to analyze sublethal effects of chronic gamma irradiation in the nematode Caenorhabditis elegans. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:830-844. [PMID: 28837407 DOI: 10.1080/15287394.2017.1352194] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Understanding how toxic contaminants affect wildlife species at various levels of biological organization (subcellular, histological, physiological, organism, and population levels) is a major research goal in both ecotoxicology and radioecology. A mechanistic understanding of the links between different observed perturbations is necessary to predict the consequences for survival, growth, and reproduction, which are critical for population dynamics. In this context, experimental and modeling studies were conducted using the nematode Caenorhabditis elegans. A chronic exposure to external gamma radiation was conducted under controlled conditions. Results showed that somatic growth and reproduction were reduced with increasing dose rate. Modeling was used to investigate whether radiation effects might be assessed using a mechanistic model based upon the dynamic energy budget (DEB) theory. A DEB theory in toxicology (DEB-tox), specially adapted to the case of gamma radiation, was developed. Modelling results demonstrated the suitability of DEB-tox for the analysis of radiotoxicity and suggested that external gamma radiation predominantly induced a direct reduction in reproductive capacity in C. elegans and produced an increase in costs for growth and maturation, resulting in a delay in growth and spawning observed at the highest tested dose rate.
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Affiliation(s)
- Catherine Lecomte-Pradines
- a Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LECO , Cadarache , Saint-Paul-lez-Durance , France
| | - Turid Hertel-Aas
- b Centre for Environmental Radioactivity (CERAD), Department of Environmental Science , Norwegian University of Life Sciences (NMBU) , Aas , Norway
| | - Claire Coutris
- b Centre for Environmental Radioactivity (CERAD), Department of Environmental Science , Norwegian University of Life Sciences (NMBU) , Aas , Norway
- c Division of Environment and Natural Resources , Norwegian Institute of Bioeconomy Research (NIBIO) , Aas , Norway
| | - Rodolphe Gilbin
- d Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LRTE , Cadarache , Saint-Paul-lez-Durance , France
| | - Deborah Oughton
- b Centre for Environmental Radioactivity (CERAD), Department of Environmental Science , Norwegian University of Life Sciences (NMBU) , Aas , Norway
| | - Frédéric Alonzo
- a Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LECO , Cadarache , Saint-Paul-lez-Durance , France
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16
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Zabinsky RA, Weum BM, Cui M, Han M. RNA Binding Protein Vigilin Collaborates with miRNAs To Regulate Gene Expression for Caenorhabditis elegans Larval Development. G3 (BETHESDA, MD.) 2017; 7:2511-2518. [PMID: 28576776 PMCID: PMC5555458 DOI: 10.1534/g3.117.043414] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 05/29/2017] [Indexed: 01/16/2023]
Abstract
Extensive studies have suggested that most miRNA functions are executed through complex miRNA-target interaction networks, and such networks function semiredundantly with other regulatory systems to shape gene expression dynamics for proper physiological functions. We found that knocking down vgln-1, which encodes a conserved RNA-binding protein associated with diverse functions, causes severe larval arrest at the early L1 stage in animals with compromised miRISC functions (an ain-2/GW182 mutant). Through an enhancer screen, we identified five specific miRNAs, and miRNA families, that act semiredundantly with VGLN-1 to regulate larval development. By RIP-Seq analysis, we identified mRNAs that are directly bound by VGLN-1, and highly enriched for miRNA binding sites, leading to a hypothesis that VGLN-1 may share common targets with miRNAs to regulate gene expression dynamics for development.
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Affiliation(s)
- Rebecca A Zabinsky
- Howard Hughes Medical Institute, University of Colorado at Boulder, Boulder, Colorado 80309
| | - Brett M Weum
- Howard Hughes Medical Institute, University of Colorado at Boulder, Boulder, Colorado 80309
| | - Mingxue Cui
- Howard Hughes Medical Institute, University of Colorado at Boulder, Boulder, Colorado 80309
| | - Min Han
- Howard Hughes Medical Institute, University of Colorado at Boulder, Boulder, Colorado 80309
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, Colorado 80309
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17
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Lažetić V, Fay DS. Molting in C. elegans. WORM 2017; 6:e1330246. [PMID: 28702275 DOI: 10.1080/21624054.2017.1330246] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/01/2017] [Accepted: 05/09/2017] [Indexed: 12/21/2022]
Abstract
Molting is an essential developmental process for the majority of animal species on Earth. During the molting process, which is a specialized form of extracellular matrix (ECM) remodeling, the old apical ECM, or cuticle, is replaced with a new one. Many of the genes and pathways identified as important for molting in nematodes are highly conserved in vertebrates and include regulators and components of vesicular trafficking, steroid-hormone signaling, developmental timers, and hedgehog-like signaling. In this review, we discuss what is known about molting, with a focus on studies in Caenorhabditis elegans. We also describe the key structural elements of the cuticle that must be released, newly synthesized, or remodeled for proper molting to occur.
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Affiliation(s)
- Vladimir Lažetić
- Department of Molecular Biology, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY, USA
| | - David S Fay
- Department of Molecular Biology, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY, USA
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18
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Viney M. How Can We Understand the Genomic Basis of Nematode Parasitism? Trends Parasitol 2017; 33:444-452. [PMID: 28274802 PMCID: PMC5449551 DOI: 10.1016/j.pt.2017.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 11/02/2022]
Abstract
Nematodes are very common animals and they have repeatedly evolved parasitic lifestyles during their evolutionary history. Recently, the genomes of many nematodes, especially parasitic species, have been determined, potentially giving an insight into the genetic and genomic basis of nematodes' parasitism. But, to achieve this, phylogenetically appropriate comparisons of genomes of free-living and parasitic species are needed. Achieving this has often been hampered by the relative lack of information about key free-living species. While such comparative approaches will eventually succeed, I suggest that a synthetic biology approach - moving free-living nematodes towards a parasitic lifestyle - will be our ultimate test of truly understanding the genetic and genomic basis of nematode parasitism.
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Affiliation(s)
- Mark Viney
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol, BS8 1TQ, UK.
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19
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Aschner M, Palinski C, Sperling M, Karst U, Schwerdtle T, Bornhorst J. Imaging metals in Caenorhabditis elegans. Metallomics 2017; 9:357-364. [DOI: 10.1039/c6mt00265j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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20
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Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin. Sci Rep 2016; 6:37346. [PMID: 27869126 PMCID: PMC5116746 DOI: 10.1038/srep37346] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 10/27/2016] [Indexed: 12/27/2022] Open
Abstract
The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time- and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.
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21
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Uppaluri S, Brangwynne CP. A size threshold governs Caenorhabditis elegans developmental progression. Proc Biol Sci 2016; 282:20151283. [PMID: 26290076 DOI: 10.1098/rspb.2015.1283] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The growth of organisms from humans to bacteria is affected by environmental conditions. However, mechanisms governing growth and size control are not well understood, particularly in the context of changes in food availability in developing multicellular organisms. Here, we use a novel microfluidic platform to study the impact of diet on the growth and development of the nematode Caenorhabditis elegans. This device allows us to observe individual worms throughout larval development, quantify their growth as well as pinpoint the moulting transitions marking successive developmental stages. Under conditions of low food availability, worms grow very slowly, but do not moult until they have achieved a threshold size. The time spent in larval stages can be extended by over an order of magnitude, in agreement with a simple threshold size model. Thus, a critical worm size appears to trigger developmental progression, and may contribute to prolonged lifespan under dietary restriction.
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Affiliation(s)
- Sravanti Uppaluri
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
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22
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Crone B, Aschner M, Schwerdtle T, Karst U, Bornhorst J. Elemental bioimaging of Cisplatin in Caenorhabditis elegans by LA-ICP-MS. Metallomics 2016; 7:1189-95. [PMID: 25996669 DOI: 10.1039/c5mt00096c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
cis-Diamminedichloroplatinum(II) (Cisplatin) is one of the most important and frequently used cytostatic drugs for the treatment of various solid tumors. Herein, a laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) method incorporating a fast and simple sample preparation protocol was developed for the elemental mapping of Cisplatin in the model organism Caenorhabditis elegans (C. elegans). The method allows imaging of the spatially-resolved elemental distribution of platinum in the whole organism with respect to the anatomic structure in L4 stage worms at a lateral resolution of 5 μm. In addition, a dose- and time-dependent Cisplatin uptake was corroborated quantitatively by a total reflection X-ray fluorescence spectroscopy (TXRF) method, and the elemental mapping indicated that Cisplatin is located in the intestine and in the head of the worms. Better understanding of the distribution of Cisplatin in this well-established model organism will be instrumental in deciphering Cisplatin toxicity and pharmacokinetics. Since the cytostatic effect of Cisplatin is based on binding the DNA by forming intra- and interstrand crosslinks, the response of poly(ADP-ribose)metabolism enzyme 1 (pme-1) deletion mutants to Cisplatin was also examined. Loss of pme-1, which is the C. elegans ortholog of human poly(ADP-ribose) polymerase 1 (PARP-1) led to disturbed DNA damage response. With respect to survival and brood size, pme-1 deletion mutants were more sensitive to Cisplatin as compared to wildtype worms, while Cisplatin uptake was indistinguishable.
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Affiliation(s)
- Barbara Crone
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstraße 30, 48149 Münster, Germany
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23
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Margerit A, Gomez E, Gilbin R. Dynamic energy-based modeling of uranium and cadmium joint toxicity to Caenorhabditis elegans. CHEMOSPHERE 2016; 146:405-412. [PMID: 26741545 DOI: 10.1016/j.chemosphere.2015.12.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 12/07/2015] [Accepted: 12/08/2015] [Indexed: 06/05/2023]
Abstract
Toxicokinetic - toxicodynamic energy-based models offer new alternatives to the commonly used approaches for the analysis of mixture toxicity data. Based on the Dynamic Energy Budget theory, DEBtox models enable the description of several endpoints over time simultaneously under the same framework. However, such model still has to be faced with experimental data in a multi-contamination context. In this study, the predictive capacities of a DEBtox model to describe the uranium and cadmium joint toxicity over the entire growth and reproduction period of the soil nematode Caenorhabditis elegans was examined. The two reference additivity approaches, Concentration Addition and Response addition, implemented in the DEBtox model were tested. Assuming no interaction between the two toxicants through Response addition, the DEBtox model allowed a rather accurate fit of the U and Cd joint effects on the growth and reproduction of C. elegans: an interaction between the two metals at the toxicokinetic or toxicodynamic level seems thus unlikely or has only minor consequences. Interestingly, this study underlines that even if the compounds of a mixture share the same DEBtox physiological mode of action (in this case a decrease in assimilation), the Response addition approach may provide a better fit of joint toxicity data than the Concentration addition approach. Moreover, the present work highlighted limitations in the model predictions which are related to the simplifications of the DEBtox framework and its adaptations to the physiology of C. elegans and which lead to an overestimation of the U and Cd joint toxicity in some cases.
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Affiliation(s)
- Adrien Margerit
- Biogeochemistry, Bioavailability and Radionuclide Transfer Laboratory (PRP-ENV/SERIS/L2BT), Institute of Radioprotection and Nuclear Safety (IRSN), Cadarache, Building 183, BP3, 13115 St-Paul-lez-Durance Cedex, France.
| | - Elena Gomez
- UMR Hydrosciences - Université Montpellier 1, DSESP - Faculté de Pharmacie, BP 14491, No 15 Av Charles Flahault, 34093 Montpellier Cedex 05, France
| | - Rodolphe Gilbin
- Biogeochemistry, Bioavailability and Radionuclide Transfer Laboratory (PRP-ENV/SERIS/L2BT), Institute of Radioprotection and Nuclear Safety (IRSN), Cadarache, Building 183, BP3, 13115 St-Paul-lez-Durance Cedex, France.
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24
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Gonzalez-Moragas L, Yu SM, Carenza E, Laromaine A, Roig A. Protective Effects of Bovine Serum Albumin on Superparamagnetic Iron Oxide Nanoparticles Evaluated in the Nematode Caenorhabditis elegans. ACS Biomater Sci Eng 2015; 1:1129-1138. [PMID: 33429554 DOI: 10.1021/acsbiomaterials.5b00253] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nanomaterials give rise to unique biological reactivity that needs to be thoroughly investigated. The quest for enhanced magnetic nanomaterials of different shapes, magnetic properties, or surface coatings continues for applications in drug delivery, targeting therapies, biosensing, and magnetic separation. In this context, the use of simple in vivo models, such as Caenorhabditis elegans, to biologically evaluate nanoparticles is currently in increasing demand as it offers low-cost and information-rich experiments. In this work, we evaluated how surface modification (citrate- and protein-coated) of superparamagnetic iron oxide nanoparticles (C-SPIONs and BSA-SPIONs, respectively) induces changes in their toxicological profile and biodistribution using the animal model C. elegans and combining techniques from materials science and biochemistry. The acute toxicity and nanoparticle distribution were assessed in two populations of worms (adults and larvae) treated with both types of SPIONs. After 24 h treatment, nanoparticles were localized in the alimentary system of C. elegans; acute toxicity was stronger in adults and larvae exposed to C-SPIONs rather than BSA-SPIONs. Adult uptake was similar for both SPION types, whereas uptake in larvae was dependent on the surface coating, being higher for BSA-SPIONs. Nanoparticle size was evaluated upon excretion, and a slight size decrease was found. Interestingly, all results indicate the protective effects of the BSA to prevent degradation of the nanoparticles and decrease acute toxicity to the worms, especially at high concentrations. We argue that this relevant information on the chemistry and toxicity of SPIONs in vivo could not be gathered using more classical in vitro approaches such as cell culture assays, thus endorsing the potential of C. elegans to assess nanomaterials at early stages of their synthetic formulations.
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Affiliation(s)
- Laura Gonzalez-Moragas
- Institut de Ciència de Materials de Barcelona, CSIC, Campus UAB, 08193 Bellaterra, Spain
| | - Si-Ming Yu
- Institut de Ciència de Materials de Barcelona, CSIC, Campus UAB, 08193 Bellaterra, Spain
| | - Elisa Carenza
- Institut de Ciència de Materials de Barcelona, CSIC, Campus UAB, 08193 Bellaterra, Spain
| | - Anna Laromaine
- Institut de Ciència de Materials de Barcelona, CSIC, Campus UAB, 08193 Bellaterra, Spain
| | - Anna Roig
- Institut de Ciència de Materials de Barcelona, CSIC, Campus UAB, 08193 Bellaterra, Spain
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25
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A new methodology for evaluation of nematode viability. BIOMED RESEARCH INTERNATIONAL 2015; 2015:879263. [PMID: 25866820 PMCID: PMC4383492 DOI: 10.1155/2015/879263] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/19/2015] [Indexed: 01/19/2023]
Abstract
Nematodes infections are responsible for debilitating conditions and economic losses in domestic animals as well as livestock and are considered an important public health problem due to the high prevalence in humans. The nematode resistance for drugs has been reported for livestock, highlighting the importance for development of new anthelmintic compounds. The aim of the current study was to apply and compare fluorimetric techniques using Sytox and propidium iodide for evaluating the viability of C. elegans larvae after treatment with anthelmintic drugs. These fluorescent markers were efficient to stain larvae treated with ivermectin and albendazole sulfoxide. We observed that densitometric values were proportional to the concentration of dead larvae stained with both markers. Furthermore, data on motility test presented an inverse correlation with fluorimetric data when ivermectin was used. Our results showed that lower concentrations of drugs were effective to interfere in the processes of cellular transport while higher drugs concentrations were necessary in order to result in any damage to cell integrity. The methodology described in this work might be useful for studies that aim to evaluate the viability of nematodes, particularly for testing of new anthelminthic compounds using an easy, economic, reproducible, and no time-consuming technique.
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26
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Goussen B, Beaudouin R, Dutilleul M, Buisset-Goussen A, Bonzom JM, Péry ARR. Energy-based modelling to assess effects of chemicals on Caenorhabditis elegans: a case study on uranium. CHEMOSPHERE 2015; 120:507-514. [PMID: 25278179 DOI: 10.1016/j.chemosphere.2014.09.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 08/27/2014] [Accepted: 09/02/2014] [Indexed: 06/03/2023]
Abstract
The ubiquitous free-living nematode Caenorhabditis elegans is a powerful animal model for measuring the evolutionary effects of pollutants which is increasingly used in (eco) toxicological studies. Indeed, toxicity tests with this nematode can provide in a few days data on the whole life cycle. These data can be analysed with mathematical tools such as toxicokinetic-toxicodynamic modelling approaches. In this study, we assessed how a chronic exposure to a radioactive heavy metal (uranium) affects the life-cycle of C. elegans using a mechanistic model. In order to achieve this, we exposed individuals to a range of seven concentrations of uranium. Growth and reproduction were followed daily. These data were analysed with a model for nematodes based on the Dynamic Energy Budget theory, able to handle a wide range of plausible biological parameters values. Parameter estimations were performed using a Bayesian framework. Our results showed that uranium affects the assimilation of energy from food with a no-effect concentration (NEC) of 0.42 mM U which would be the threshold for effects on both growth and reproduction. The sensitivity analysis showed that the main contributors to the model output were parameters linked to the feeding processes and the actual exposure concentration. This confirms that the real exposure concentration should be measured accurately and that the feeding parameters should not be fixed, but need to be reestimated during the parameter estimation process.
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Affiliation(s)
- Benoit Goussen
- Unité Modèles pour l'Ecotoxicologie et la Toxicologie (METO), Institut National de l'Environnement Industriel et des Risques (INERIS), BP2, F-60550 Verneuil en Halatte, France; Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, Laboratoire d'ECOtoxicologie des radionucléides (LECO), Cadarache, France.
| | - Rémy Beaudouin
- Unité Modèles pour l'Ecotoxicologie et la Toxicologie (METO), Institut National de l'Environnement Industriel et des Risques (INERIS), BP2, F-60550 Verneuil en Halatte, France
| | - Morgan Dutilleul
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, Laboratoire d'ECOtoxicologie des radionucléides (LECO), Cadarache, France
| | - Adeline Buisset-Goussen
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, Laboratoire d'ECOtoxicologie des radionucléides (LECO), Cadarache, France
| | - Jean-Marc Bonzom
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, Laboratoire d'ECOtoxicologie des radionucléides (LECO), Cadarache, France
| | - Alexandre R R Péry
- Unité Modèles pour l'Ecotoxicologie et la Toxicologie (METO), Institut National de l'Environnement Industriel et des Risques (INERIS), BP2, F-60550 Verneuil en Halatte, France
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27
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George-Raizen JB, Shockley KR, Trojanowski NF, Lamb AL, Raizen DM. Dynamically-expressed prion-like proteins form a cuticle in the pharynx of Caenorhabditis elegans. Biol Open 2014; 3:1139-49. [PMID: 25361578 PMCID: PMC4232772 DOI: 10.1242/bio.20147500] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In molting animals, a cuticular extracellular matrix forms the first barrier to infection and other environmental insults. In the nematode Caenorhabditis elegans there are two types of cuticle: a well-studied collagenous cuticle lines the body, and a poorly-understood chitinous cuticle lines the pharynx. In the posterior end of the pharynx is the grinder, a tooth-like cuticular specialization that crushes food prior to transport to the intestine for digestion. We here show that the grinder increases in size only during the molt. To gain molecular insight into the structure of the grinder and pharyngeal cuticle, we performed a microarray analysis to identify mRNAs increased during the molt. We found strong transcriptional induction during the molt of 12 of 15 previously identified abu genes encoding Prion-like (P) glutamine (Q) and asparagine (N) rich PQN proteins, as well as 15 additional genes encoding closely related PQN proteins. abu/pqn genes, which we name the abu/pqn paralog group (APPG) genes, were expressed in pharyngeal cells and the proteins encoded by two APPG genes we tested localized to the pharyngeal cuticle. Deleting the APPG gene abu-14 caused abnormal pharyngeal cuticular structures and knocking down other APPG genes resulted in abnormal cuticular function. We propose that APPG proteins promote the assembly and function of a unique cuticular structure. The strong developmental regulation of the APPG genes raises the possibility that such genes would be identified in transcriptional profiling experiments in which the animals' developmental stage is not precisely staged.
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Affiliation(s)
- Julia B George-Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Keith R Shockley
- Biostatistics Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Nicholas F Trojanowski
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Annesia L Lamb
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA Present address: Department of Earth and Environmental Sciences, The Graduate Center, The City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - David M Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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28
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Li WH, Ju YR, Liao CM, Liao VHC. Assessment of selenium toxicity on the life cycle of Caenorhabditis elegans. ECOTOXICOLOGY (LONDON, ENGLAND) 2014; 23:1245-1253. [PMID: 24906985 DOI: 10.1007/s10646-014-1267-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/22/2014] [Indexed: 06/03/2023]
Abstract
Selenium (Se) is a growing problem of global concern. Se can cause adverse effects on reproductive systems, which have been linked to declines in animal populations. The soil nematode Caenorhabditis elegans (C. elegans) is a ubiquitous soil organism that is increasingly utilized as a model organism in aquatic and soil toxicology. In the present study, the experimental data for individual body length, survival rate, brood size, and hatching rate were used to evaluate the possible effects of selenite [Se(IV)] on C. elegans. A stage-classified matrix model was applied to the experimental data to provide information on the population dynamics of C. elegans and to assess the Se(IV)-affected asymptotic population growth rate. Estimates of the survival probability showed significant decreases in survival at all stages when C. elegans was exposed to Se(IV). The growth probability of C. elegans in the L1 stage showed the most significant decline, from 0.11 h(-1) (for the control) to 0.04 h(-1) [for exposure to 3 mM Se(IV)]. These results showed that Se(IV) has a profound impact on C. elegans population dynamics. The asymptotic population growth rate (λ) was found to range from 1.00 to 0.64 h(-1) for increasing Se(IV) concentrations, implying a potential risk of population decrease for C. elegans exposure to a Se(IV)-contaminated environment. Our study shows how a mechanistic view based on the Se(IV) effects on the soil nematode C. elegans can promote a life cycle toxicity assessment. An important implication of this analysis is that mathematical models can be used to produce a population stage structure, to give clarity to the analysis of the key population-level endpoint (the asymptotic population growth rate) of population dynamics, and to evaluate the influences for the response of other species to environmental Se. These models sequentially provide candidate environmental criteria for the evaluation of the population impact of Se.
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Affiliation(s)
- Wen-Hsuan Li
- Department of Bioenvironmental Systems Engineering, National Taiwan University, No. 1 Roosevelt Road, Sec. 4, Taipei, 106, Taiwan
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29
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Avery L. A model of the effect of uncertainty on the C elegans L2/L2d decision. PLoS One 2014; 9:e100580. [PMID: 25029446 PMCID: PMC4100763 DOI: 10.1371/journal.pone.0100580] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/24/2014] [Indexed: 12/17/2022] Open
Abstract
At the end of the first larval stage, the C elegans larva chooses between two developmental pathways, an L2 committed to reproductive development and an L2d, which has the option of undergoing reproductive development or entering the dauer diapause. I develop a quantitative model of this choice using mathematical tools developed for pricing financial options. The model predicts that the optimal decision must take into account not only the expected potential for reproductive growth, but also the uncertainty in that expected potential. Because the L2d has more flexibility than the L2, it is favored in unpredictable environments. I estimate that the ability to take uncertainty into account may increase reproductive value by as much as 5%, and discuss possible experimental tests for this ability.
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Affiliation(s)
- Leon Avery
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Identification of late larval stage developmental checkpoints in Caenorhabditis elegans regulated by insulin/IGF and steroid hormone signaling pathways. PLoS Genet 2014; 10:e1004426. [PMID: 24945623 PMCID: PMC4063711 DOI: 10.1371/journal.pgen.1004426] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/20/2014] [Indexed: 01/10/2023] Open
Abstract
Organisms in the wild develop with varying food availability. During periods of nutritional scarcity, development may slow or arrest until conditions improve. The ability to modulate developmental programs in response to poor nutritional conditions requires a means of sensing the changing nutritional environment and limiting tissue growth. The mechanisms by which organisms accomplish this adaptation are not well understood. We sought to study this question by examining the effects of nutrient deprivation on Caenorhabditis elegans development during the late larval stages, L3 and L4, a period of extensive tissue growth and morphogenesis. By removing animals from food at different times, we show here that specific checkpoints exist in the early L3 and early L4 stages that systemically arrest the development of diverse tissues and cellular processes. These checkpoints occur once in each larval stage after molting and prior to initiation of the subsequent molting cycle. DAF-2, the insulin/insulin-like growth factor receptor, regulates passage through the L3 and L4 checkpoints in response to nutrition. The FOXO transcription factor DAF-16, a major target of insulin-like signaling, functions cell-nonautonomously in the hypodermis (skin) to arrest developmental upon nutrient removal. The effects of DAF-16 on progression through the L3 and L4 stages are mediated by DAF-9, a cytochrome P450 ortholog involved in the production of C. elegans steroid hormones. Our results identify a novel mode of C. elegans growth in which development progresses from one checkpoint to the next. At each checkpoint, nutritional conditions determine whether animals remain arrested or continue development to the next checkpoint. Organisms in the wild often face long periods in which food is scarce. This may occur due to seasonal effects, loss of territory, or changes in predator-to-prey ratio. During periods of scarcity, organisms undergo adaptations to conserve resources and prolong survival. When nutrient deprivation occurs during development, physical growth and maturation to adulthood is delayed. These effects are also observed in malnourished individuals, who are smaller and reach puberty at later ages. Developmental arrest in response to nutrient scarcity requires a means of sensing changing nutrient conditions and coordinating an organism-wide response. How this occurs is not well understood. We assessed the developmental response to nutrient withdrawal in the nematode worm Caenorhabditis elegans. By removing food in the late larval stages, a period of extensive tissue formation, we have uncovered previously unknown checkpoints that occur at precise times in development. Diverse tissues and cellular processes arrest at the checkpoints. Insulin-like signaling and steroid hormone signaling regulate tissue arrest following nutrient withdrawal. These pathways are conserved in mammals and are linked to growth processes and diseases. Given that the pathways that respond to nutrition are conserved in animals, it is possible that similar checkpoints may also be important in human development.
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31
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Jager T, Gudmundsdóttir EM, Cedergreen N. Dynamic modeling of sublethal mixture toxicity in the nematode Caenorhabditis elegans. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:7026-7033. [PMID: 24857627 DOI: 10.1021/es501306t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Dynamic models for toxic effects [toxicokinetic-toxicodynamic (TKTD) models] are increasingly used in the analysis of toxicity data for single-chemical exposure. However, these models also offer a natural extension to the effects of chemical mixtures. Here, we demonstrate how a simple model for the energy budget (DEBkiss) can be used to interpret the effects of cadmium and fluoranthene, in both single and mixed exposure, on the nematode Caenorhabditis elegans. The data for all time points and all end points (growth and reproduction) are combined into a single coherent framework. These modeling results are compared to a more traditional independent-action approach based on the dose-response curves for a single end point at a single time point. The analysis with DEBkiss does not lead to a radically different interpretation of the mixture effects, both indicating an antagonistic interaction in the mixture. The DEBkiss analysis does, however, provide much more insight into the relevant dynamic processes underlying the toxic effect on the organism and allows for the generation of mechanistic hypotheses that can be used to guide further research.
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Affiliation(s)
- Tjalling Jager
- Department of Theoretical Biology, VU University Amsterdam , de Boelelaan 1085, NL-1081 HV Amsterdam, Netherlands
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32
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Maxwell CS, Kruesi WS, Core LJ, Kurhanewicz N, Waters CT, Lewarch CL, Antoshechkin I, Lis JT, Meyer BJ, Baugh LR. Pol II docking and pausing at growth and stress genes in C. elegans. Cell Rep 2014; 6:455-66. [PMID: 24485661 PMCID: PMC4026043 DOI: 10.1016/j.celrep.2014.01.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 11/01/2013] [Accepted: 01/06/2014] [Indexed: 11/25/2022] Open
Abstract
Fluctuations in nutrient availability profoundly impact gene expression. Previous work revealed postrecruitment regulation of RNA polymerase II (Pol II) during starvation and recovery in Caenorhabditis elegans, suggesting that promoter-proximal pausing promotes rapid response to feeding. To test this hypothesis, we measured Pol II elongation genome wide by two complementary approaches and analyzed elongation in conjunction with Pol II binding and expression. We confirmed bona fide pausing during starvation and also discovered Pol II docking. Pausing occurs at active stress-response genes that become downregulated in response to feeding. In contrast, "docked" Pol II accumulates without initiating upstream of inactive growth genes that become rapidly upregulated upon feeding. Beyond differences in function and expression, these two sets of genes have different core promoter motifs, suggesting alternative transcriptional machinery. Our work suggests that growth and stress genes are both regulated postrecruitment during starvation but at initiation and elongation, respectively, coordinating gene expression with nutrient availability.
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Affiliation(s)
- Colin S Maxwell
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - William S Kruesi
- Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Leighton J Core
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Nicole Kurhanewicz
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - Colin T Waters
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Caitlin L Lewarch
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - Igor Antoshechkin
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Barbara J Meyer
- Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - L Ryan Baugh
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA.
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Hendriks GJ, Gaidatzis D, Aeschimann F, Großhans H. Extensive oscillatory gene expression during C. elegans larval development. Mol Cell 2014; 53:380-92. [PMID: 24440504 DOI: 10.1016/j.molcel.2013.12.013] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 11/25/2013] [Accepted: 12/12/2013] [Indexed: 10/25/2022]
Abstract
Oscillations are a key to achieving dynamic behavior and thus occur in biological systems as diverse as the beating heart, defecating worms, and nascent somites. Here we report pervasive, large-amplitude, and phase-locked oscillations of gene expression in developing C. elegans larvae, caused by periodic transcription. Nearly one fifth of detectably expressed transcripts oscillate with an 8 hr period, and hundreds change >10-fold. Oscillations are important for molting but occur in all phases, implying additional functions. Ribosome profiling reveals that periodic mRNA accumulation causes rhythmic translation, potentially facilitating transient protein accumulation as well as coordinated production of stable, complex structures such as the cuticle. Finally, large-amplitude oscillations in RNA sampled from whole worms indicate robust synchronization of gene expression programs across cells and tissues, suggesting that these oscillations will be a powerful new model to study coordinated gene expression in an animal.
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Affiliation(s)
- Gert-Jan Hendriks
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland; University of Basel, Petersplatz 1, CH-4003 Basel, Switzerland
| | - Dimos Gaidatzis
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland; Swiss Institute of Bioinformatics, CH-4058 Basel, Switzerland
| | - Florian Aeschimann
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland; University of Basel, Petersplatz 1, CH-4003 Basel, Switzerland
| | - Helge Großhans
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
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34
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Tuck S. The control of cell growth and body size in Caenorhabditis elegans. Exp Cell Res 2013; 321:71-6. [PMID: 24262077 DOI: 10.1016/j.yexcr.2013.11.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 01/02/2023]
Abstract
One of the most important ways in which animal species vary is in their size. Individuals of the largest animal ever thought to have lived, the blue whale (Balaenoptera musculus), can reach a weight of 190 t and a length of over 30 m. At the other extreme, among the smallest multicellular animals are males of the parasitic wasp, Dicopomorpha echmepterygis, which even as adults are just 140 μm in length. In terms of volume, these species differ by more than 14 orders of magnitude. Since size has such profound effects on an organism's ecology, anatomy and physiology, an important task for evolutionary biology and ecology is to account for why organisms grow to their characteristic sizes. Equally, a full description of an organism's development must include an explanation of how its growth and body size are regulated. Here I review research on how these processes are controlled in the nematode, Caenorhabditis elegans. Analyses of small and long mutants have revealed that in the worm, DBL-1, a ligand in the TGFβ superfamily family, promotes growth in a dose-dependent manner. DBL-1 signaling affects body size by stimulating the growth of syncytial hypodermal cells rather than controlling cell division. Signals from chemosensory neurons and from the gonad also modulate body size, in part, independently of DBL-1-mediated signaling. Organismal size and morphology is heavily influenced by the cuticle, which acts as the exoskeleton. Finally, I summarize research on several genes that appear to regulate body size by cell autonomously regulating cell growth throughout the worm.
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Affiliation(s)
- Simon Tuck
- Umeå Center for Molecular Medicine, Umeå University, SE-901 87 Umeå, Sweden.
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35
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Kim DH, Grün D, van Oudenaarden A. Dampening of expression oscillations by synchronous regulation of a microRNA and its target. Nat Genet 2013; 45:1337-44. [PMID: 24036951 PMCID: PMC3812263 DOI: 10.1038/ng.2763] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 08/22/2013] [Indexed: 11/09/2022]
Abstract
The complexity of multicellular organisms requires precise spatiotemporal regulation of gene expression during development. We find that in the nematode Caenorhabditis elegans approximately 2,000 transcripts undergo expression oscillations synchronized with larval transitions while thousands of genes are expressed in temporal gradients, similar to known timing regulators. By counting transcripts in individual worms, we show that pulsatile expression of the microRNA (miRNA) lin-4 maintains the temporal gradient of its target lin-14 by dampening its expression oscillations. Our results demonstrate that this insulation is optimal when pulsatile expression of the miRNA and its target is synchronous. We propose that such a miRNA-mediated incoherent feed-forward loop is a potent filter that prevents the propagation of potentially deleterious fluctuations in gene expression during the development of an organism.
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Affiliation(s)
- Dong hyun Kim
- 1] Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [2] Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [3]
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36
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Synapse location during growth depends on glia location. Cell 2013; 154:337-50. [PMID: 23870123 DOI: 10.1016/j.cell.2013.06.028] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 04/09/2013] [Accepted: 06/19/2013] [Indexed: 11/22/2022]
Abstract
Synaptic contacts are largely established during embryogenesis and are then maintained during growth. To identify molecules involved in this process, we conducted a forward genetic screen in C. elegans and identified cima-1. In cima-1 mutants, synaptic contacts are correctly established during embryogenesis, but ectopic synapses emerge during postdevelopmental growth. cima-1 encodes a solute carrier in the SLC17 family of transporters that includes sialin, a protein that when mutated in humans results in neurological disorders. cima-1 does not function in neurons but rather functions in the nearby epidermal cells to correctly position glia during postlarval growth. Our findings indicate that CIMA-1 antagonizes the FGF receptor (FGFR), and does so most likely by inhibiting FGFR's role in epidermal-glia adhesion rather than signaling. Our data suggest that epidermal-glia crosstalk, in this case mediated by a transporter and the FGF receptor, is vital to preserve embryonically derived circuit architecture during postdevelopmental growth.
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37
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Monsalve GC, Frand AR. Toward a unified model of developmental timing: A "molting" approach. WORM 2013; 1:221-30. [PMID: 24058853 PMCID: PMC3670223 DOI: 10.4161/worm.20874] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 05/24/2012] [Indexed: 02/06/2023]
Abstract
Animal development requires temporal coordination between recurrent processes and sequential events, but the underlying timing mechanisms are not yet understood. The molting cycle of C. elegans provides an ideal system to study this basic problem. We recently characterized LIN-42, which is related to the circadian clock protein PERIOD, as a key component of the developmental timer underlying rhythmic molting cycles. In this context, LIN-42 coordinates epithelial stem cell dynamics with progression of the molting cycle. Repeated actions of LIN-42 may enable the reprogramming of seam cell temporal fates, while stage-specific actions of LIN-42 and other heterochronic genes select fates appropriate for upcoming, rather than passing, life stages. Here, we discuss the possible configuration of the molting timer, which may include interconnected positive and negative regulatory loops among lin-42, conserved nuclear hormone receptors such as NHR-23 and -25, and the let-7 family of microRNAs. Physiological and environmental conditions may modulate the activities of particular components of this molting timer. Finding that LIN-42 regulates both a sleep-like behavioral state and epidermal stem cell dynamics further supports the model of functional conservation between LIN-42 and mammalian PERIOD proteins. The molting timer may therefore represent a primitive form of a central biological clock and provide a general paradigm for the integration of rhythmic and developmental processes.
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Affiliation(s)
- Gabriela C Monsalve
- Department of Biological Chemistry; David Geffen School of Medicine; University of California; Los Angeles, CA USA
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38
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Sun J, Xie H, Qiu J, Liu X, Xiang M. Parasitism of secondary-stage juvenile of Heterodera glycines and four larva stages of Caenorhabditis elegans by Hirsutella spp. Exp Parasitol 2013; 135:96-101. [PMID: 23831035 DOI: 10.1016/j.exppara.2013.06.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 06/17/2013] [Accepted: 06/24/2013] [Indexed: 10/26/2022]
Abstract
The fungi Hirsutella rhossiliensis and Hirsutella minnesotensis generally parasitize only plant-parasitic nematodes in nature but parasitize the bacterivorous nematode Caenorhabditis elegans on agar plates. To establish a model system for studying the interaction between fungi and nematodes, we compared the parasitism of the first- to fourth-stage larvae (L1-L4) of C. elegans and second-stage juvenile (J2) of Heterodera glycines by twenty isolates of Hirsutella spp. Although parasitism differed substantially among isolates, both H. minnesotensis and H. rhossiliensis parasitized a higher percentage of H. glycines J2s than of C. elegans larvae. Parasitism of C. elegans L1s was correlated with parasitism of H. glycines J2s. Parasitism of C. elegans by H. rhossiliensis and H. minnesotensis was negatively correlated with larva size and motility, i.e., parasitism was higher for the younger stages. The C. elegans L1 is recommended for studying parasitism of nematodes by H. rhossiliensis and H. minnesotensis.
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Affiliation(s)
- Jingzu Sun
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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39
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Moore BT, Jordan JM, Baugh LR. WormSizer: high-throughput analysis of nematode size and shape. PLoS One 2013; 8:e57142. [PMID: 23451165 PMCID: PMC3579787 DOI: 10.1371/journal.pone.0057142] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 01/17/2013] [Indexed: 12/05/2022] Open
Abstract
The fundamental phenotypes of growth rate, size and morphology are the result of complex interactions between genotype and environment. We developed a high-throughput software application, WormSizer, which computes size and shape of nematodes from brightfield images. Existing methods for estimating volume either coarsely model the nematode as a cylinder or assume the worm shape or opacity is invariant. Our estimate is more robust to changes in morphology or optical density as it only assumes radial symmetry. This open source software is written as a plugin for the well-known image-processing framework Fiji/ImageJ. It may therefore be extended easily. We evaluated the technical performance of this framework, and we used it to analyze growth and shape of several canonical Caenorhabditis elegans mutants in a developmental time series. We confirm quantitatively that a Dumpy (Dpy) mutant is short and fat and that a Long (Lon) mutant is long and thin. We show that daf-2 insulin-like receptor mutants are larger than wild-type upon hatching but grow slow, and WormSizer can distinguish dauer larvae from normal larvae. We also show that a Small (Sma) mutant is actually smaller than wild-type at all stages of larval development. WormSizer works with Uncoordinated (Unc) and Roller (Rol) mutants as well, indicating that it can be used with mutants despite behavioral phenotypes. We used our complete data set to perform a power analysis, giving users a sense of how many images are needed to detect different effect sizes. Our analysis confirms and extends on existing phenotypic characterization of well-characterized mutants, demonstrating the utility and robustness of WormSizer.
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Affiliation(s)
- Brad T. Moore
- PhD Program in Computational Biology and Bioinformatics, Duke University, Durham, North Carolina, United States of America
| | - James M. Jordan
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - L. Ryan Baugh
- Department of Biology, Duke University, Durham, North Carolina, United States of America
- Duke Center for Systems Biology, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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40
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Ayub F, Strauch O, Seychelles L, Ehlers RU. Influence of temperature on life history traits of the free-living, bacterial-feeding nematode Panagrolaimus sp. strain NFS-24. NEMATOLOGY 2013. [DOI: 10.1163/15685411-00002732] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Life cycle analysis data of the free-living, bacterial-feeding Panagrolaimus sp. strain NFS 24-5 were assessed at different temperatures using a hanging drop method with single male and female individuals and a food density of 3 × 109 Escherichia coli cells ml−1. Lifespan at the moment when the first egg was laid was 5.7 days at 21°C and 4 days at 25, 27 and 29°C. The intrinsic rate of natural increase () was 0.53 at 21°C, 0.81 at 25°C, 0.93 at 27°C and 0.81 at 29°C, corresponding to population doubling times () of 1.3, 0.9, 0.7 and 0.9 days, respectively. Over 200 offspring per female were produced at 27°C. All other temperatures yielded fewer offspring. When females were kept without males, the life span was 49 days, whereas the last reproductive female (hanging drop with male individual) died after 16.5 days. These data will contribute to the interpretation of nematode population dynamics recorded in liquid culture.
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Affiliation(s)
- Farhana Ayub
- Faculty of Agricultural and Nutritional Science, Christian-Albrechts-University Kiel, Olshausenstrasse 40, 24098 Kiel, Germany
| | - Olaf Strauch
- e-nema GmbH, Klausdorfer Strasse 28-36, 24223 Schwentinental, Germany
| | - Laurent Seychelles
- Faculty of Agricultural and Nutritional Science, Christian-Albrechts-University Kiel, Olshausenstrasse 40, 24098 Kiel, Germany
| | - Ralf-Udo Ehlers
- e-nema GmbH, Klausdorfer Strasse 28-36, 24223 Schwentinental, Germany
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41
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Palgunow D, Klapper M, Döring F. Dietary restriction during development enlarges intestinal and hypodermal lipid droplets in Caenorhabditis elegans. PLoS One 2012. [PMID: 23185233 PMCID: PMC3502458 DOI: 10.1371/journal.pone.0046198] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Dietary restriction (DR) extends lifespan in man species and modulates evolutionary conserved signalling and metabolic pathways. Most of these studies were done in adult animals. Here we investigated fat phenotypes of C. elegans larvae and adults which were exposed to DR during development. This approach was named "developmental-DR" (dDR). Moderate as well as stringent dDR increased the triglyceride to protein ratio in L4 larvae and adult worms. This alteration was accompanied by a marked expansion of intestinal and hypodermal lipid droplets. In comparison to ad libitum condition, the relative proportion of fat stored in large lipid droplets (>50 µm(3)) was increased by a factor of about 5 to 6 in larvae exposed to dDR. Microarray-based expression profiling identified several dDR-regulated genes of lipolysis and lipogenesis which may contribute to the observed fat phenotypes. In conclusion, dDR increases the triglyceride to protein ratio, enlarges lipid droplets and alters the expression of genes functioning in lipid metabolism in C. elegans. These changes might be an effective adaptation to conserve fat stores in animals subjected to limiting food supply during development.
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Affiliation(s)
| | | | - Frank Döring
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Kiel, Germany
- * E-mail:
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42
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Chisholm AD, Hsiao TI. The Caenorhabditis elegans epidermis as a model skin. I: development, patterning, and growth. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 1:861-78. [PMID: 23539299 DOI: 10.1002/wdev.79] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The skin of the nematode Caenorhabditis elegans is composed of a simple epidermal epithelium and overlying cuticle. The skin encloses the animal and plays central roles in body morphology and physiology; its simplicity and accessibility make it a tractable genetic model for several aspects of skin biology. Epidermal precursors are specified by a hierarchy of transcriptional regulators. Epidermal cells form on the dorsal surface of the embryo and differentiate to form the epidermal primordium, which then spreads out in a process of epiboly to enclose internal tissues. Subsequent elongation of the embryo into a vermiform larva is driven by cell shape changes and cell fusions in the epidermis. Most epidermal cells fuse in mid-embryogenesis to form a small number of multinucleate syncytia. During mid-embryogenesis the epidermis also becomes intimately associated with underlying muscles, performing a tendon-like role in transmitting muscle force. Post-embryonic development of the epidermis involves growth by addition of new cells to the syncytia from stem cell-like epidermal seam cells and by an increase in cell size driven by endoreplication of the chromosomes in epidermal nuclei.
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Affiliation(s)
- Andrew D Chisholm
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA.
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43
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Monsalve GC, Van Buskirk C, Frand AR. LIN-42/PERIOD controls cyclical and developmental progression of C. elegans molts. Curr Biol 2011; 21:2033-45. [PMID: 22137474 DOI: 10.1016/j.cub.2011.10.054] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 10/07/2011] [Accepted: 10/31/2011] [Indexed: 01/06/2023]
Abstract
BACKGROUND Biological timing mechanisms that integrate cyclical and successive processes are not well understood. C. elegans molting cycles involve rhythmic cellular and animal behaviors linked to the periodic reconstruction of cuticles. Molts are coordinated with successive transitions in the temporal fates of epidermal blast cells, which are programmed by genes in the heterochronic regulatory network. It was known that juveniles molt at regular 8-10 hr intervals, but the anticipated pacemaker had not been characterized. RESULTS We find that inactivation of the heterochronic gene lin-42a, which is related to the core circadian clock gene PERIOD (PER), results in arrhythmic molts and continuously abnormal epidermal stem cell dynamics. The oscillatory expression of lin-42a in the epidermis peaks during the molts. Further, forced expression of lin-42a leads to anachronistic larval molts and lethargy in adults. CONCLUSIONS Our results suggest that rising and falling levels of LIN-42A allow the start and completion, respectively, of larval molts. We propose that LIN-42A and affiliated factors regulate molting cycles in much the same way that PER-based oscillators drive rhythmic behaviors and metabolic processes in mature mammals. Further, the combination of reiterative and stage-specific functions of LIN-42 may coordinate periodic molts with successive development of the epidermis.
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Affiliation(s)
- Gabriela C Monsalve
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
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44
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Volume electron microscopy for neuronal circuit reconstruction. Curr Opin Neurobiol 2011; 22:154-61. [PMID: 22119321 DOI: 10.1016/j.conb.2011.10.022] [Citation(s) in RCA: 204] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 10/19/2011] [Accepted: 10/27/2011] [Indexed: 11/23/2022]
Abstract
The last decade has seen a rapid increase in the number of tools to acquire volume electron microscopy (EM) data. Several new scanning EM (SEM) imaging methods have emerged, and classical transmission EM (TEM) methods are being scaled up and automated. Here we summarize the new methods for acquiring large EM volumes, and discuss the tradeoffs in terms of resolution, acquisition speed, and reliability. We then assess each method's applicability to the problem of reconstructing anatomical connectivity between neurons, considering both the current capabilities and future prospects of the method. Finally, we argue that neuronal 'wiring diagrams' are likely necessary, but not sufficient, to understand the operation of most neuronal circuits: volume EM imaging will likely find its best application in combination with other methods in neuroscience, such as molecular biology, optogenetics, and physiology.
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Zhang H, Abraham N, Khan LA, Hall DH, Fleming JT, Göbel V. Apicobasal domain identities of expanding tubular membranes depend on glycosphingolipid biosynthesis. Nat Cell Biol 2011; 13:1189-201. [PMID: 21926990 PMCID: PMC3249144 DOI: 10.1038/ncb2328] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 07/28/2011] [Indexed: 02/06/2023]
Abstract
Metazoan internal organs are assembled from polarized tubular epithelia that must set aside an apical membrane domain as a lumenal surface. In a global Caenorhabditis elegans tubulogenesis screen, interference with several distinct fatty-acid-biosynthetic enzymes transformed a contiguous central intestinal lumen into multiple ectopic lumens. We show that multiple-lumen formation is caused by apicobasal polarity conversion, and demonstrate that in situ modulation of lipid biosynthesis is sufficient to reversibly switch apical domain identities on growing membranes of single post-mitotic cells, shifting lumen positions. Follow-on targeted lipid-biosynthesis pathway screens and functional genetic assays were designed to identify a putative single causative lipid species. They demonstrate that fatty-acid biosynthesis affects polarity through sphingolipid synthesis, and reveal ceramide glucosyltransferases (CGTs) as end-point biosynthetic enzymes in this pathway. Our findings identify glycosphingolipids, CGT products and obligate membrane lipids, as critical determinants of in vivo polarity and indicate that they sort new components to the expanding apical membrane.
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Affiliation(s)
- Hongjie Zhang
- Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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Katiki LM, Ferreira JFS, Zajac AM, Masler C, Lindsay DS, Chagas ACS, Amarante AFT. Caenorhabditis elegans as a model to screen plant extracts and compounds as natural anthelmintics for veterinary use. Vet Parasitol 2011; 182:264-8. [PMID: 21680095 DOI: 10.1016/j.vetpar.2011.05.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/13/2011] [Accepted: 05/16/2011] [Indexed: 01/12/2023]
Abstract
The most challenging obstacles to testing products for their anthelmintic activity are: (1) establishing a suitable nematode in vitro assay that can evaluate potential product use against a parasitic nematode of interest and (2) preparation of extracts that can be redissolved in solvents that are miscible in the test medium and are at concentrations well tolerated by the nematode system used for screening. The use of parasitic nematodes as a screening system is hindered by the difficulty of keeping them alive for long periods outside their host and by the need to keep infected animals as sources of eggs or adults when needed. This method uses the free-living soil nematode Caenorhabditis elegans as a system to screen products for their potential anthelmintic effect against small ruminant gastrointestinal nematodes, including Haemonchus contortus. This modified method uses only liquid axenic medium, instead of agar plates inoculated with Escherichia coli, and two selective sieves to obtain adult nematodes. During screening, the use of either balanced salt solution (M-9) or distilled water resulted in averages of 99.7 (± 0.73)% and 96.36 (± 2.37)% motile adults, respectively. Adult worms tolerated DMSO, ethanol, methanol, and Tween 80 at 1% and 2%, while Labrasol (a bioenhancer with low toxicity to mammals) and Tween 20 were toxic to C. elegans at 1% and were avoided as solvents. The high availability, ease of culture, and rapid proliferation of C. elegans make it a useful screening system to test plant extracts and other phytochemical compounds to investigate their potential anthelmintic activity against parasitic nematodes.
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Affiliation(s)
- Luciana M Katiki
- Instituto de Zootecnia (SAA,APTA), Rua Heitor Penteado 56, Nova Odessa, SP, cep 13460-000, Brazil
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Lucanic M, Held JM, Vantipalli MC, Klang IM, Graham JB, Gibson BW, Lithgow GJ, Gill MS. N-acylethanolamine signalling mediates the effect of diet on lifespan in Caenorhabditis elegans. Nature 2011; 473:226-9. [PMID: 21562563 PMCID: PMC3093655 DOI: 10.1038/nature10007] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 03/17/2011] [Indexed: 02/01/2023]
Abstract
Dietary restriction (DR) is a robust means of extending adult lifespan and postponing age-related disease in many species, including yeast, worms, flies and rodents1,2. Studies of the genetic requirements for lifespan extension by DR in the nematode Caenorhabditis elegans (C. elegans) have implicated a number of key players in this process3–5, including the nutrient-sensing target of rapamycin (TOR) pathway6 and the Foxa transcription factor PHA-47. However, little is known about the metabolic signals that coordinate the organismal response to DR and maintain homeostasis when nutrients are limited. The endocannabinoid (EC) system is an excellent candidate to play such a role given its involvement in regulating nutrient intake and energy balance8. Despite this, a direct role for EC signaling in DR or lifespan determination has yet to be demonstrated, in part due to the apparent absence of EC signaling pathways in model organisms that are amenable to lifespan analysis9. N-acylethanolamines (NAEs) are lipid-derived signaling molecules, which include the mammalian EC arachidonoyl ethanolamide (AEA). Here we identify NAEs in C. elegans, show that NAE abundance is reduced under DR and that NAE deficiency is sufficient to extend lifespan through a DR mechanism requiring PHA-4. Conversely, dietary supplementation with the nematode NAE eicosapentaenoyl ethanolamide (EPEA) not only inhibits DR-induced lifespan extension in wild type animals, but also suppresses lifespan extension in a TOR pathway mutant. This demonstrates a role for NAE signaling in aging and suggests that NAEs represent a signal that coordinates nutrient status with metabolic changes that ultimately determine lifespan.
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Affiliation(s)
- Mark Lucanic
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, California 94945, USA
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Molecular mechanism of size control in development and human diseases. Cell Res 2011; 21:715-29. [PMID: 21483452 DOI: 10.1038/cr.2011.63] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
How multicellular organisms control their size is a fundamental question that fascinated generations of biologists. In the past 10 years, tremendous progress has been made toward our understanding of the molecular mechanism underlying size control. Original studies from Drosophila showed that in addition to extrinsic nutritional and hormonal cues, intrinsic mechanisms also play important roles in the control of organ size during development. Several novel signaling pathways such as insulin and Hippo-LATS signaling pathways have been identified that control organ size by regulating cell size and/or cell number through modulation of cell growth, cell division, and cell death. Later studies using mammalian cell and mouse models also demonstrated that the signaling pathways identified in flies are also conserved in mammals. Significantly, recent studies showed that dysregulation of size control plays important roles in the development of many human diseases such as cancer, diabetes, and hypertrophy.
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Bhaskaran S, Butler JA, Becerra S, Fassio V, Girotti M, Rea SL. Breaking Caenorhabditis elegans the easy way using the Balch homogenizer: an old tool for a new application. Anal Biochem 2011; 413:123-32. [PMID: 21354098 DOI: 10.1016/j.ab.2011.02.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 02/03/2011] [Accepted: 02/18/2011] [Indexed: 11/19/2022]
Abstract
The nematode Caenorhabditis elegans is a model organism best known for its powerful genetics. There is an increasing need in the worm community to couple genetics with biochemistry. Isolation of functionally active proteins or nucleic acids without the use of strong oxidizing denaturants or of subcellular compartments from C. elegans has, however, been challenging because of the worms' thick surrounding cuticle. The Balch homogenizer is a tool that has found much use in mammalian cell culture biology. The interchangeable single ball-bearing design of this instrument permits rapid permeabilization, or homogenization, of cells. Here we demonstrate the utility of the Balch homogenizer for studies with C. elegans. We describe procedures for the efficient breakage and homogenization of every larval stage, including dauers, and show that the Balch homogenizer can be used to extract functionally active proteins. Enzymatic assays for catalase and dihydrolipoamide dehydrogenase show that sample preparation using the Balch homogenizer equals or outperforms conventional methods employing boiling, sonication, or Dounce homogenization. We also describe phenol-free techniques for isolation of genomic DNA and RNA. Finally, we used the tool to isolate coupled mitochondria and polysomes. The reusable Balch homogenizer represents a quick and convenient solution for undertaking biochemical studies on C. elegans.
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Affiliation(s)
- Shylesh Bhaskaran
- Barshop Institute for Longevity and Aging Studies and Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78240, USA
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Tarailo-Graovac M, Wang J, Chu JSC, Tu D, Baillie DL, Chen N. Spindle assembly checkpoint genes reveal distinct as well as overlapping expression that implicates MDF-2/Mad2 in postembryonic seam cell proliferation in Caenorhabditis elegans. BMC Cell Biol 2010; 11:71. [PMID: 20858267 PMCID: PMC2955571 DOI: 10.1186/1471-2121-11-71] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 09/21/2010] [Indexed: 01/31/2023] Open
Abstract
Background The spindle assembly checkpoint (SAC) delays anaphase onset by inhibiting the activity of the anaphase promoting complex/cyclosome (APC/C) until all of the kinetochores have properly attached to the spindle. The importance of SAC genes for genome stability is well established; however, the roles these genes play, during postembryonic development of a multicellular organism, remain largely unexplored. Results We have used GFP fusions of 5' upstream intergenic regulatory sequences to assay spatiotemporal expression patterns of eight conserved genes implicated in the spindle assembly checkpoint function in Caenorhabditis elegans. We have shown that regulatory sequences for all of the SAC genes drive ubiquitous GFP expression during early embryonic development. However, postembryonic spatial analysis revealed distinct, tissue-specific expression of SAC genes with striking co-expression in seam cells, as well as in the gut. Additionally, we show that the absence of MDF-2/Mad2 (one of the checkpoint genes) leads to aberrant number and alignment of seam cell nuclei, defects mainly attributed to abnormal postembryonic cell proliferation. Furthermore, we show that these defects are completely rescued by fzy-1(h1983)/CDC20, suggesting that regulation of the APC/CCDC20 by the SAC component MDF-2 is important for proper postembryonic cell proliferation. Conclusion Our results indicate that SAC genes display different tissue-specific expression patterns during postembryonic development in C. elegans with significant co-expression in hypodermal seam cells and gut cells, suggesting that these genes have distinct as well as overlapping roles in postembryonic development that may or may not be related to their established roles in mitosis. Furthermore, we provide evidence, by monitoring seam cell lineage, that one of the checkpoint genes is required for proper postembryonic cell proliferation. Importantly, our research provides the first evidence that postembryonic cell division is more sensitive to SAC loss, in particular MDF-2 loss, than embryonic cell division.
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Affiliation(s)
- Maja Tarailo-Graovac
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
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