The effects of metals and food availability on the behavior of Caenorhabditis elegans

Author: Boyd, W.A.; Cole, R.D.; Anderson, G.L.; Williams, P.L. Description: Caenorhabditis elegans, a nonparasitic soil nematode, was used to assess the combined effects of metal exposures and food availability on behavior. Movement was monitored using a computer tracking system after exposures to Cu, Pb, or Cd while feeding was measured as a change in optical density (deltaOD) of bacteria suspensions over the exposure period. After 24-h exposures at high and low bacteria concentrations, movement was decreased in a concentration-dependent fashion by Pb and Cd but feeding reductions were not directly…

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Development of the reproductive system of Caenorhabditis elegans

Author: Hirsh, D.; Oppenheim, D.; Klass, M. Description: A morphological study of the growth and the development of the reproductive system of the nematode Caenorhabditis elegans has been carried out. When the first stage larva hatches from the egg it contains four primordial gonadial cells. These cells proliferate and form the entire adult reproductive system, consisting of approximately 2500 nuclei, in 45 hr at 25°C. Several distinctive morphological featues of gonadogenesis and early embryogenesis that are recognizable in the compound microscope can be used to chart the development of the…

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Metabolic shift from glycogen to trehalose promotes lifespan and healthspan in Caenorhabditis elegans

Author: Seo, Y., Kingsley, S., Walker, G., Mondoux, M. A., & Tissenbaum, H. A. Description: As Western diets continue to include an ever-increasing amount of sugar, there has been a rise in obesity and type 2 diabetes. To avoid metabolic diseases, the body must maintain proper metabolism, even on a high-sugar diet. In both humans and Caenorhabditis elegans, excess sugar (glucose) is stored as glycogen. Here, we find that animals increased stored glycogen as they aged, whereas even young adult animals had increased stored glycogen on a high-sugar diet. Decreasing…

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High-glucose diets induce mitochondrial dysfunction in Caenorhabditis elegans

Author: Alcántar-Fernández, J., González-Maciel, A., Reynoso-Robles, R., Andrade, M. E. P., Hernández-Vázquez, A. d. J., Velázquez-Arellano, A., & Miranda-Ríos, J. Description: Glucose is an important nutrient that dictates the development, fertility and lifespan of all organisms. In humans, a deficit in its homeostatic control might lead to hyperglucemia and the development of obesity and type 2 diabetes, which show a decreased ability to respond to and metabolize glucose. Previously, we have reported that high-glucose diets (HGD) induce alterations in triglyceride content, body size, progeny, and the mRNA accumulation of key…

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Development of the reproductive system of Caenorhabditis elegans

Author: Hirsh, D.; Oppenheim, D.; Klass, M. Description: A morphological study of the growth and the development of the reproductive system of the nematode Caenorhabditis elegans has been carried out. When the first stage larva hatches from the egg it contains four primordial gonadial cells. These cells proliferate and form the entire adult reproductive system, consisting of approximately 2500 nuclei, in 45 hr at 25°C. Several distinctive morphological featues of gonadogenesis and early embryogenesis that are recognizable in the compound microscope can be used to chart the development of the…

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Caenorhabditis elegans ras gene let-60 acts as a switch in the pathway of vulval induction

Author: Beitel, G.J.; Clark, S.G.; Horvitz, H.R. Description: The let-60 gene, an essential ras gene of the nematode Caenorhabditis elegans, acts as a switch in the inductive signalling pathway that initiates vulva formation. Recessive let-60 mutations that cause a vulvaless phenotype prevent let-60 function in response to the inductive signal. These mutations are clustered and define regions necessary either for the activation or for the action of the let-60 ras protein. Dominant let-60 mutations that cause a multivulva phenotype alter codon 13 and activate let-60 in vivo, rendering it independent…

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Male mating behavior

Author: Barr, M. M., Garcia, L. R. Description: Caenorhabditis elegans male mating provides an excellent opportunity to determine how sensory perception regulates behavior and motor programs. The male-specific nervous system and muscles are superimposed over the general nervous system and musculature. Genetic screens and genomic approaches have identified male-specific and male-enriched genes as well as non-sex specific molecules specialized for mating sub-behaviors. In this chapter, we discuss the cellular, genetic, and molecular basis for male mating behavior. Subject headings: Animals; Caenorhabditis elegans/anatomy & histology; Caenorhabditis elegans/physiology; Ejaculation; Female; Male; Sex…

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Neural regulation of thermotaxis in Caenorhabditis elegans

Author: Mori, I.; Ohshima, Y. Description: Thermal stimulus is an important environmental factor influencing animal behavior. However, the mechanisms underlying thermosensation and thermal adaptation are poorly understood. The nematode Caenorhabditis elegans can sense a range of environmental temperatures and migrate towards the cultivation temperature on a thermal gradient. This modifiable thermotactic response provides an ideal system for studying the cellular and molecular processes involved in thermosensation and thermal information storage. We have identified neurons critical for thermotaxis by killing individual cells in live animals. The results indicate that an amphid…

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Mutations in the unc-54 myosin heavy chain gene of Caenorhabditis elegans that alter contractility but not muscle structure

Author: Moerman, D.G.; Plurad, S.; Waterston, R.H.; Baillie, D.L. Description: Reversion analysis of mutants of unc-22 IV, a gene affecting muscle structure and function in Caenorhabditis elegans, led to the isolation of six extragenic dominant suppressors of the “twitching” phenotype of unc-22 mutants. All six suppressors are new alleles of unc-54 I, the major body wall myosin heavy chain gene. Homozygous suppressor strains are slow, stiff and have normal muscle structure, whereas previously identified unc-54 alleles confer flaccid paralysis and drastic reduction in thick filament number and organization. Placement of…

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Rebaudioside A Enhances Resistance to Oxidative Stress and Extends Lifespan and Healthspan in Caenorhabditis elegans

Author: Li, Pan; Wang, Zehua; Lam, Sin Man; Shui, Guanghou Description: Non-nutritive sweeteners are widely used in food and medicines to reduce energy content without compromising flavor. Herein, we report that Rebaudioside A (Reb A), a natural, non-nutritive sweetener, can extend both the lifespan and healthspan of C. elegans. The beneficial effects of Reb A were principally mediated via reducing the level of cellular reactive oxygen species (ROS) in response to oxidative stress and attenuating neutral lipid accumulation with aging. Transcriptomics analysis presented maximum differential expression of genes along the…

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