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[
Worm Breeder's Gazette,
1994]
Dpy-27: A Protein Required for Dosage Compensation Is Associated with the X chromosome in XX Animals Pao-Tien Chuangl, Donna Albertson2 and Barbara Meyerl, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720~ and MRC Laboratory of Molecular biology, Hills Road, Cambridge, CB2 2QH UK2
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[
International Worm Meeting,
2015]
Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons and aggregation of alpha-synuclein (AS) protein leading to motor and cognitive impairment. The current study investigates the role of Alaskan bog blueberry (Vaccinum uliginosum), on alpha synuclein aggregation using a transgenic model of Caenorhabditis elegans expressing human alpha-synuclein [NL5901 (P(
unc-54)::alpha-synuclein::YFP+
unc-119)].The current study also examines the role of Sirtuin 1, a histone deacetylase, in reducing the toxicity of alpha-synuclein aggregates and whether this effect is mediated via expression of molecular chaperones, HSP1 and HSP70. The Alaskan bog blueberry was chosen for its high phenolic content, because phenolics have been shown to modulate sirtuin-mediated molecular pathways. Our experiments showed that the crude extract of low bog blueberry (400 and 800 ug/ml) reduced alpha-synuclein aggregation. For high-dose blueberry extract (800 ug/ml), the protection was mediated by sirtuin and HSF-1, which is independent of HSP 70. These findings encourage further studies on these Alaskan botanicals as possible therapeutic agents for Parkinson's disease, specifically of interest are the identification of active ingredients within the extracts and their optimal doses.
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[
International Worm Meeting,
2017]
The C. elegans pharynx is a tubular, bi-lobed, muscular pump encased in a basement membrane. The pharynx muscle contracts and relaxes as the animal feeds, generating a characteristic electrical signal that can be recorded as an "electropharyngeogram". The frequency of pharyngeal pumping decreases with age and is considered a reliable index of overall health. Recently, NemaMetrix has made available a device that easily monitors and quantifies the C. elegans electropharyngeogram. We have designed a two-week teaching module using the NemaMetrix platform in guided undergraduate research. Projects assay a locally relevant environmental toxin, a natural product, and the effect of age in C. elegans. We provide examples of research projects that can be done in a two-week research module as part of a biomedically-related undergraduate course.
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[
Nat Methods,
2011]
Engineering precise genetic changes in a genome is powerful way to study gene function, and several recent papers describe new applications of gene-editing tools. Working with researchers at Sangamo BioSciences, Howard Hughes Medical Institute investigator Barbara Meyer and her colleagues at the University of California, Berkeley, described the first systems for making targeted genomic modifications in the roundworm Caenorhabditis elegans, a valuable model organism (Wood et al., 2011).
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[
International Worm Meeting,
2015]
The most common method of C. elegans transfer is to use a fine sterilized "pick" made of hair or wire to move animals individually or in small groups. Many procedures, such as RNA extraction or fluorescent imaging, require a large sample of synchronized animals of reproductive age for accurate results. Without expensive sorting equipment, researchers are left to manually select and transfer individual animals. To address this need, we built a low-cost (under $10), easy-to-make device to efficiently select and move large numbers of nematodes from plate to plate without the use of a pick, FUDR, or high-cost sorting machines. Our transfer procedure uses a filtration device created with common lab supplies, and a standard buffer solution. The conceptual approach is to filter a population of animals through a fine mesh attached to a plastic cap, then rinse off leftover unwanted animals and debris from the mesh into a disposable tube. The device is then flipped over and the selected animals are rinsed off the filter into a collection tube where they can settle by gravity, after which they are pipetted into or onto a fresh media source. We will present data comparing our method to the current pick selection method in terms of percent yield of filtered animals, use in large scale assays, and several health parameters, including motility, pump rate, fecundity, and activation of stress response genes.
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[
Genetics,
2019]
The Genetics Society of America's (GSA) Thomas Hunt Morgan Medal honors researchers for lifetime achievement in genetics. The recipient of the 2018 Morgan Medal, Barbara J. Meyer of the Howard Hughes Medical Institute and the University of California, Berkeley, is recognized for her career-long, groundbreaking investigations of how chromosome behaviors are controlled. Meyer's work has revealed mechanisms of sex determination and dosage compensation in <i>Caenorhabditis elegans</i> that continue to serve as the foundation of diverse areas of study on chromosome structure and function today, nearly 40 years after she began her work on the topic.
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[
International Worm Meeting,
2019]
In C. elegans, the feeding behavior of pharyngeal pumping occurs spontaneously in proportion to metabolism and in response to stimuli. Age- and health-related changes in tissue morphology and function correlate with declines in the frequency of pumping. As such, pumping frequency is an established index of C. elegans "health", and pumping changes illustrate and quantify functional decline. Timing of pharyngeal pumping is controlled by pharyngeal motor neurons (MC and M3). Each pump cycle corresponds to the propagation of a single pharyngeal muscle action potential, initiated by MC and transmitted across a single neuromuscular junction. We currently model this system with MC acting as a rhythmic oscillator, synaptically linked to the pharyngeal muscle. Pumping can change by influences on the pace and/or regularity of the oscillator, and by changes in pharyngeal muscle response to neuronal inputs. Traditionally, pumping is reported as an occurrence frequency, quantified by counting pump event occurring over an observation period. However this quantification has limit resolution; may be confounded by variation in pumping between subjects; and fails to distinguish potentially distinct mechanisms influencing pace and regularity of the MC neuron, or the fidelity of the neuromuscular junction. We have developed an analysis strategy and algorithm (WormBeat) that normalizes variation between subjects, enhances resolution of subtle treatment effects, distinguish neuromuscular fidelity from MC neuron pace, and separates random pace variation from directed modulation of the MC neuron. This presentation describes the theory and practice of the algorithm, its validation using simulated events with known variability, and its application to electrophysiological recordings of pharyngeal pumping in vivo.
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Parker, J. Alex, Nichols, Courtney Rose, Driscoll, Monica, Neri, Christian, Vayndorf, Elena, Taylor, Barbara
[
International Worm Meeting,
2013]
Neurodegenerative diseases, such as Huntington's, Alzheimer's, and Parkinson's disease, result in the progressive loss of neuronal structure and function with age. Many neurodegenerative disorders are caused by genetic mutations and characterized by toxic aggregation of proteins within neurons. We explored the mechanism of accelerated neuronal aging in a polyglutamine (polyQ) protein aggregation model through genetic manipulation. Caenorhabditis elegans expressing the first 57 amino acids of human huntingtin protein with a toxic polyglutamine chain (polyQ128) fluorescently labeled with CFP in YFP-labeled mechanosensory neurons (Parker et al, 2001) were used to monitor neuronal aging phenotypes. We found an age-associated increase in aberrant neuronal morphology, protein aggregation, and functional impairment of the mechanosensory neurons expressing toxic 128 polyQ. We also tested the hypothesis that the insulin signaling pathway is involved in morphological and functional health of aging mechanosensory neurons using neuron-specific RNA interference (RNAi). Furthermore, we measured levels of endogenous oxidative stress and lifespan of aging animals that contain toxic polyQ128 repeats following RNAi manipulation of the insulin signaling pathway. Overall, we found that DAF-16/FOXO is neuroprotective in this accelerated aging model, which corroborates previous findings on the role of DAF-16/FOXO in polyQ128 young adults (Parker et al. 2005). To further characterize overall muscle and neuronal health, we measured action potentials of pharyngeal muscle contractions and neurons that innervate the pharynx using microfluidic electropharyngeography (EPG). In total, our observations support that insulin signaling via DAF-16/FOXO is a mechanism through which accelerated aging and neurodegeneration occurs in this model.
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Mitra, Swarup, Maulik, Malabika, Taylor, Barbara, Vayndorf, Elena, Hunter, Skyler, Bult-Ito, Abel
[
International Worm Meeting,
2017]
Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons and aggregation of alpha-synuclein (AS) protein leading to motor and cognitive impairment. The current study investigates the role of Alaskan bog blueberry (Vaccinum uliginosum), on alpha synuclein aggregation using a transgenic model of Caenorhabditis elegans expressing human alpha-synuclein [OW13 (P(
unc-54)::alpha-synuclein::YFP+
unc-119)].The current study also examines the role of Sirtuin 1, a histone deacetylase, in reducing the toxicity of alpha-synuclein aggregates and whether this effect is mediated via expression of other downstream molecular targets. The Alaskan bog blueberry was chosen for its high phenolic content, because phenolics have been shown to modulate sirtuin-mediated molecular pathways. Our experiments showed that the crude extract of low bog blueberry ( 100 and 400 ug/ml) reduced alpha-synuclein aggregation and improved motility in the worm model. The study also highlights the molecular mechanism through which the botanicals are exerting this beneficial effect. These findings encourage further studies on these Alaskan botanicals as possible therapeutic agents for Parkinson's disease, specifically of interest are the identification of active ingredients within the extracts and their optimal doses.
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Hunter, Skyler, Driscoll, Monica, Toth, Marton, Scerbak, Courtney, Taylor, Barbara, Neri, Christian, Parker, J. Alex, Vayndorf, Elena
[
International Worm Meeting,
2015]
In both C. elegans and humans, the aging nervous system is characterized by decreased synaptic activity, deteriorating short-term and long-term memory, and altered neuronal morphology. Given the overwhelming evidence for proteostasis disruption in neuronal aging, we sought to explain the accumulation of neuronal morphological abnormalities by focusing on protein homeostasis in 6 mechanosensory neurons of aging C. elegans nematodes. We examined the effects of disrupted proteostasis on the integrity of neuronal cytoarchitecture using a transgenic model with an excessively high neuronal protein load, and RNAi knock down of specific genes involved in protein turnover. We found that animals expressing the first 57 amino acids of the human huntingtin gene and an expanded polyglutamine CAG tract (Q128) in mechanosensory neurons accumulate more aberrations that are distinct from those found in animals that express the non-toxic (Q19) number of repeats, or those that express no repeats. We scored and tallied these changes in both the soma and processes and found that they are sometimes associated with improved or reduced function. Next, we used an RNAi candidate gene approach to target genes involved in the maintenance of protein homeostasis in wild-type animals. We found that genes involved in protein turnover play an important role in maintaining the integrity of healthy neurons, and that their knockdown leads to distinct morphological changes in both the process and the soma of wild-type mechanosensory neurons. Taken together, these results suggest that protein homeostasis is critical for maintaining neuronal integrity and function, and that disrupted proteostasis contributes to morphological abnormalities that occur more frequently with advanced age.