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J Neurogenet
]
A slide taped to a window at the Woods Hole Marine Biology Laboratory was my first introduction to the touch receptor neurons of the nematode <i>Caenorhabditis elegans</i>. Studying these cells as a postdoc with Sydney Brenner gave me a chance to work with John Sulston on a fascinating set of neurons. I would never have guessed then that 43 years later I would still be excited about learning their secrets.
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Development,
2018]
John Sulston, a pioneer in the developmental studies of the nematode <i>C. elegans</i> who went on to spearhead the sequencing of the genome of this organism and ultimately the human genome, died on 6th March 2018, shortly after being diagnosed with stomach cancer. Here, I reflect on John's life and work, with a particular focus on his time working on the developmental genetics and lineage of <i>C. elegans</i><i>.</i>
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Curr Protoc Mol Biol,
2018]
RNAi is a powerful reverse genetics tool that has revolutionized genetic studies in model organisms. The bacteriovorous nematode Caenorhabditis elegans can be genetically manipulated by feeding it an Escherichia coli strain that expresses a double-stranded RNA (dsRNA) corresponding to a C. elegans gene, which leads to systemic silencing of the gene. This unit describes protocols for performing an automated high-throughput RNAi screen utilizing a full-genome C. elegans RNAi library. The protocols employ liquid-handling robotics and 96-well plates. 2018 by John Wiley & Sons, Inc.
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J Neurogenet,
2020]
Sexual dimorphism is a device that supports genetic diversity while providing selective pressure against speciation. This phenomenon is at the core of sexually reproducing organisms. <i>Caenorhabditis elegans</i> provides a unique experimental system where males exist in a primarily hermaphroditic species. Early works of John Sulston, Robert Horvitz, and John White provided a complete map of the hermaphrodite nervous system, and recently the male nervous system was added. This addition completely realized the vision of <i>C. elegans</i> pioneer Sydney Brenner: a model organism with an entirely mapped nervous system. With this 'connectome' of information available, great strides have been made toward understanding concepts such as how a sex-shared nervous system (in hermaphrodites and males) can give rise to sex-specific functions, how neural plasticity plays a role in developing a dimorphic nervous system, and how a shared nervous system receives and processes external cues in a sexually-dimorphic manner to generate sex-specific behaviors. In <i>C. elegans</i>, the intricacies of male-mating behavior have been crucial for studying the function and circuitry of the male-specific nervous system and used as a model for studying human autosomal dominant polycystic kidney disease (ADPKD). With the emergence of CRISPR, a seemingly limitless tool for generating genomic mutations with pinpoint precision, the <i>C. elegans</i> model system will continue to be a useful instrument for pioneering research in the fields of behavior, reproductive biology, and neurogenetics.
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Parasitol Today,
1993]
Arrested development dramatically alters the life history of some species of soil-transmitted nematodes and elicits profound variations in the epidemiology of the infections they cause. Here, Peter Hotez, John Hawdon and Gerhard Schad show how an understanding of the cellular and molecular bases of arrested development may lead to new approaches for the control of ancylostomiasis and related infections.
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Curr Protoc Mol Biol,
2017]
Forward genetic analysis using chemical mutagenesis in model organisms is a powerful tool for investigation of molecular mechanisms in biological systems. In the nematode, Caenorhabditis elegans, mutagenesis screens using ethyl methanesulfonate (EMS) have led to important insights into genetic control of animal development and physiology. A major bottleneck to this approach is identification of the causative mutation underlying a phenotype of interest. In the past, this has required time-consuming genetic mapping experiments. More recently, next-generation sequencing technologies have allowed development of new methods for rapid mapping and identification of EMS-induced lesions. In this unit we describe a protocol to map and identify EMS-induced mutations in C. elegans. 2017 by John Wiley & Sons, Inc.
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Curr Protoc Neurosci,
2018]
In this unit, we describe an inexpensive and versatile method for optogenetic stimulation of a large population of genetically engineered Caenorhabditis elegans worms while quantitatively analyzing behavior. A custom light-emitting diode light source is used to deliver blue-light stimuli, causing direct depolarization of neurons expressing the light-gated cation channel Channelrhodopsin-2, which in turn evokes behavioral responses. The behavioral responses are recorded by a high-throughput machine vision-based tracking system, the Multi-Worm Tracker, for detailed analysis. This approach allows researchers to bypass technical obstacles to simultaneously deliver uniform stimuli to a large number of freely behaving animals and investigate the neural underpinnings of behavior. 2018 by John Wiley & Sons, Inc.
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Curr Protoc Mol Biol,
2018]
Automated or semi-automated high-throughput RNAi screens are highly prone to systematic errors because of multistep repetitive protocols and extensive use of automated instruments. A well-designed RNAi library can help detect and minimize systematic human and robotic errors. In this unit, we describe how to design an RNAi bacterial library for use in conjunction with the well-studied nematode Caenorhabditis elegans for automated phenotypic screens. We provide strategies to design and assemble RNAi libraries to reduce or eliminate systematic errors. These strategies serve as a good quality-control check and facilitate obtaining high-quality data from a genome-wide and sub-library RNAi screen. 2018 by John Wiley & Sons, Inc.
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J Neurogenet
]
John Sulston changed the way we do science, not once, but three times - initially with the complete cell lineage of the nematode <i>Caenorhabditis elegans</i>, next with completion of the genome sequences of the worm and human genomes and finally with his strong and active advocacy for open data sharing. His contributions were widely recognized and in 2002 he received the Nobel Prize in Physiology and Medicine.
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Curr Protoc Toxicol,
2016]
Response via noxious stimulus can be an important indicator of sensory neuron function and overall health of an organism. If the stimulation is quick and simple, and the animal can be rescued afterwards, such a method not only allows for assays pertaining to changed sensory ability after various treatments, but also increases the reliability of the statistical relationships that are established. This protocol demonstrates a stimulation assay in Caenorhabditis elegans, using blue light from common laboratory equipment: the fluorescent microscope. The nematode detects blue light using a set of amphid ciliary sensory neurons, and blue light is detrimental to its overall health after a prolonged exposure. However, under brief exposure, blue light stimulation provides a rapid and easy method for quantifying sensory functions and health without harming the animal. 2016 by John Wiley & Sons, Inc.