Weeks, Janis et al. (2021) International Worm Meeting "Comparison of electrophysiological and motility assays to study drug effects in C. elegans"

Heisler, Iring, Roberts, William, Kulke, Daniel, Hahnel, Steffen, Weeks, Janis

[International Worm Meeting, 2021]

Lanier, Vincent et al. (2021) International Worm Meeting "High-throughput EPG recordings reveal the food exploitation-exploration trade-off"

Lanier, Vincent, Lockery, Shawn, Millet, Jonathan, Weeks, Janis, Roberts, William

[International Worm Meeting, 2021]

Whole-animal screens complement traditional screens based on cultured cells and single-celled organisms. In C. elegans, two of the most common whole-animals screens involve locomotion and pharyngeal pumping. Whereas high-throughput locomotion screens are in wide use, high-throughput pharyngeal screens are lacking. Electrophysiological measures of pharyngeal activity - electropharyngeograms (EPGs) - offer higher temporal resolution and signal to noise ratio than manual or optical methods. Recently, the ease and efficiency of EPGs was improved by placing individual worms in tight-fitting microchannels. Electrical resistance formed where the worm contacts the channel walls generates voltage differences sufficient to resolve individual pharyngeal action potentials. However, this approach is currently limited to only eight worms per recording. To address this deficiency, we explored the utility of bulk EPG recordings made by increasing the length and width of the recording channel to accommodate hundreds or even thousands of worms. In bulk recordings, where worms are loosely arrayed in the channel and unrestrained, the voltage signal produced by each worm is insufficient to resolve individual action potentials. However, the composite voltage signal, which can be conceptualized as the sum of many individual, asynchronous EPGs, can be analyzed by computing its power spectrum. We found that EPG power spectra generally have just two peaks: a low frequency peak at 0-2 Hz, and a high frequency peak at 4-6 Hz. Using serotonin dose-response curves, optogenetic inhibition of pharyngeal muscles, and pharyngeal pumping mutants, we found that the high frequency peak reflects neurogenic pumping whereas the low frequency peak reflects myogenic pumping together with locomotion. As serotonin concentration is increased, the high and low frequency peaks are enlarged and diminished, respectively. We propose that the high frequency peak reflects the proportion of worms that are nearly stationary but feeding vigorously (exploitation), whereas the low frequency peak reflects the proportion of worms that are moving rapidly but feeding intermittently (exploration). Thus, the new method quantifies not only neurogenic pharyngeal pumping, but also the distribution of animals across these mutually exclusive behavioral states.

Keith Bradnam et al. (2002) European Worm Meeting "Recent changes and improvements to the WormBase database"

WormBase Consortium, Keith Bradnam

[European Worm Meeting, 2002]

WormBase is a repository of mapping, sequencing and phenotypic information for C. elegans and some closely related nematodes. New releases of the database are made freely available to the community every two weeks. The principal way in which researchers can access this data is through our website (www.wormbase.org).

Vanfleteren JR (1991) International C. elegans Meeting "OXIDATIVE STRESS RESISTANCE AND LONGEVITY IN C. ELEGANS."

Vanfleteren JR

[International C. elegans Meeting, 1991]

A previous report on the increased resistance of the long living mutation age-l to hydrogen peroxide (Larsen,P & Varshavsky, A., 1989 Meeting on C. elegans) prompted us to initiate a biochemical approach to longevity and oxidative stress defense mechanisms in C. elegans. The enzymatic activities of glutathione peroxidase, catalase and superoxide dismutase (SOD) were assayed in homogenates prepared from ageing cohorts (1, 2 and 3 weeks) of TJ412 (age-l, fer-15) and BA713 ( fer-15). Glutathione peroxidase was barely, if at all, detectable by a conventional method. Assaying exogeneous glutathione peroxidase (from hovine erythorcytes) showed no inactivation of the enzyme by inhibitors in the homogenates. Possibly this enzyme is not present in C. elegans. Catalase activity did not appear to vary with age initially (l and 2 weeks old worms), but later on, in the very senescent stage (3 weeks old) the activity of this enzyme decreased dramatically in the normal-lived control strain BA713, whereas it appeared to increase in the long-lived strain TJ412. Embryonating eggs contained much lower catalase activities. SOD activity increased linearly with age in TJ412, whereas it remained unchanged in BA713. The increase of SOD activity was exclusively due to the cuprozinc enzyme, the activity of the managanese form remaining essentially constant throughout life. Correspondingly TJ412 was found to be hyperresistant to paraquat. The level of superoxide anion production decreased initially in both BA713 and TJ412 as the worms passed from the reproductive into the post-reproductive (2 weeks old) stage. Superoxide anion production then continued to decrease in senescent (3 weeks old) BA713, hut tended to stabilize in TJ412. We conclude that overexpression of the anti-oxigenic enzymes catalase and superoxide dismutase increases life expectancy in C. elegans, though these enzymes may not determine the onset of the aging process hy themselves. The multiple effects observed in TJ412 suggest that age-l may encode a regulatory protein.

Banse, Stephen A. et al. (2013) International Worm Meeting "Microfluidic devices for electrical measures of pharyngeal health."

Weeks, Janis C., Robinson, Kristin J., Willis, John. H., Phillips, Patrick C., Lockery, Shawn R., Banse, Stephen A.

[International Worm Meeting, 2013]

The conventional method of health span screening in C. elegans currently faces three critical barriers: the absence of rigorously standardized culture conditions, the difficulty of performing longitudinal studies on individuals, and the challenge of high-throughput quantification of feeding behavior, one of the most reliable measures of health and a predictor of longevity in the worm. Whereas new microfluidic technologies are being developed to provide controlled growth chambers that minimize the first two challenges, the technology to automate measurements of feeding behavior is lagging behind. In C. elegans aging research, pump rate (0-5 Hz) is currently recorded and analyzed manually by direct observation of slow-motion videos of single worms while feeding on agar plates. It currently takes 5 hours to record and analyze 10 minutes of video, a 30:1 ratio that has become a bottleneck in C. elegans aging research, particularly in health-span screens requiring large data sets. We have devised an alternative approach using a recently developed microfluidic device for recording the electrical activity of the pharynx - an electropharyngeogram (EPG). These recordings can be made on eight or more worms at once, and analyzed computationally to extract pump frequencies, as well as higher-order pump features not visible in videos. Consistent with traditional measures, EPGs reveal generalized decay in pharyngeal pumping with age, with effects revealing themselves as early as 5 days. Additionally, we observe that interventions that slow aging have clear EPG phenotypes. We believe that compared to traditional video analysis, this approach will be more amenable to automation, less subjective, and provide a more information-rich readout of pharyngeal health. Additionally, this technology presents the possibility of combining EPG with other microfluidic devices to create arrays of sealed, individually addressable culture chambers that permit longitudinal assays of feeding behavior and other established measures of C. elegans health in tens, and ultimately hundreds, of worms at a time.

Olson, Sara K. et al. (2013) International Worm Meeting "A semester-long investigative lab provides an authentic research experience in the cell biology of C. elegans embryos."

Olson, Sara K., Morgens, David

[International Worm Meeting, 2013]

Undergraduate biology education should provide students with authentic research experiences that allow them to think and act as scientists. The recent push to replace "cookbook" labs with inquiry-based investigative projects provides students with a more authentic research experience. At Pomona College, upper and lower division courses contain investigative laboratory components that typically last 1-4 weeks. In the fall semester of 2012, we piloted an investigative lab in an Advanced Cell Biology course that lasted an entire semester and was based on the research interests of the Olson Lab - C. elegans eggshell formation. Each lab group was assigned a different protein that was identified in a previous RNAi screen for genes involved in eggshell formation. None of the proteins were previously characterized, though worm strains expressing mCherry fusions were created prior to the start of the semester. Students spent the first 8 weeks conducting cell biological experiments on their assigned protein, learning methods such as worm picking, co-IP, mass spectrometry, Western blotting, RNAi, IF, and live cell fluorescence microscopy. Students then wrote a paper in the style of a journal article that highlighted their main findings, suggested a model for how their protein was involved in eggshell formation, and proposed future experiments that took into account current literature and classmates' data. Students then spent the next 5-6 weeks conducting experiments to address their hypotheses and proposed future directions. The students showed characteristics typical of dedicated scientists, such as taking ownership of "their proteins", returning voluntarily at night and on weekends to complete experiments, and being critical/skeptical of experiments conducted by other groups that did not meet perceived standards of experimental rigor. The investigative lab was a win-win for everyone. Students developed practical skills and learned what being a scientist is really like, while our research lab benefitted through generation of preliminary data for new projects and the recruitment of 5 new students to the lab (out of 20 enrolled in the course).

Tuomaala, Joel et al. (2021) International Worm Meeting "Decline of ribosomal proteins levels during L1 arrest"

Towbin, Benjamin, Dengjel, Jorn, Tuomaala, Joel

[International Worm Meeting, 2021]

Starvation of C. elegans upon hatching causes developmental arrest. Arrested animals can survive for more than to 2 weeks in the absence of food and restart growth when nutrition improves. However, upon re-feeding animals resume growth with a delay that increases proportionally with the duration of starvation. Survival during starvation requires autophagy, and the starvation response is under tight control by metabolic signaling. For example, we found that mutants with constitutively active mTOR signaling die within 1 week of starvation. The goal of this project is to characterize the dynamics of proteome turnover during starvation and during recovery, and to ask if specific proteins are preferentially degraded during starvation to maintain survival. We hypothesize that under extended periods of starvation proteins needed for growth and biosynthesis, such as ribosomes and mitochondria, are preferentially turned over, as compared to structural proteins that are essential for survival, such as collagens or histones. Resuming growth upon feeding would consequently require re-synthesis of the biosynthesis proteins, and thereby delay onset of growth in proportion to the duration of starvation. To test this hypothesis, we established an assay for protein quantification based on HiBit technology. HiBit relies on a split luciferase and allows for detection of specific proteins at high accuracy and sensitivity in a microplate-based readout. Using this assay, we find that indeed ribosomal proteins declined continuously during L1 arrest. We will now test if this decline relies on autophagy, and if the turnover rate of ribosomes can explain how survival is affected in mutants with perturbed autophagy and growth signalling. Finally, we will use proteomics to assess how the proteome composition globally changes during L1 arrest on a time scale of weeks.

John Spieth et al. (2002) Mid-west Worm Meeting "WormBase; An Update"

WormBase Consortium, John Spieth

[Mid-west Worm Meeting, 2002]

WormBase is an international consortium of biologists and computer scientists dedicated to providing the research community with accurate, current, and easily accessible genetic, sequence and phenotypic information for C. elegans and a few closely-related nematodes. This information is accessed through our website (www.wormbase.org). The database is also freely available with new releases being made every two weeks. The database is constantly improving through the curation of existing data and the addition of new datasets. With the goal of making all the data easily available, improvements to the website and the addition of data mining tools are continuely being made. Recent improvements and ongoing projects will be presented. Feedback, question and contributions from the C. elegans, as well as the broader biomedical, community are welcome and encouraged and can be made by emailing to wormbase-help@wormbase.org

Darlene Maloney et al. (2005) International Worm Meeting "Use of C. elegans In Introductory Biology As a Means To Teach Experimental Design"

Patsy Dickinson, Darlene Maloney, Michael Palopoli

[International Worm Meeting, 2005]

Part of the introductory biology sequence at Bowdoin College is a lab-based course that focuses on experimental design and the undergraduate laboratory experience. The course is divided each semester into two modules that each take seven weeks to complete. Within each module, students are introduced to a system in which they can conduct independent research. One such module we have developed involves looking at the effects of chemicals on aspects of C. elegans behavior, such as chemotaxis and egg laying. Students are shown how to work with the worms through introductory experiments involving chemotaxis toward diacetyl, and egg laying in the presence of serotonin. Working in groups, they then formulate their own questions, design and carry out experiments, and analyze and report the results. We have found that this model system allows introductory biology students to ask both basic and more complex questions and to answer those questions through independent research.

Lo, Te-Wen et al. (2013) International Worm Meeting "Advances in Targeted Genome Editing Across Species: Heritable Designer "Knock-In" and "Knock-Out" Modifications."

Pickle, Catherine, Schartner, Caitlin, Anderson, Erika, Ralston, Ed, Gurling, Mark, Lo, Te-Wen, Meyer, Barbara J.

[International Worm Meeting, 2013]

We have achieved targeted genome editing across nematode species diverged by 300 million years. These methods have proven to be invaluable for evolutionary studies across species that lack reverse genetic tools but have sequenced genomes. Our editing protocols work in parasitic nematodes (P. pacificus), male/female species (C. sp.9), and hermaphroditic species (C. elegans and C. briggsae). Our approach uses engineered nucleases made of fusions between the DNA cleavage domain of FokI and a custom-designed DNA-binding domain of transcription activator-like effector (TALE) repeats. Our protocols permit not only the isolation of "knock-out" mutations, but also the recovery of multiple different custom-designed "knock-in" mutations in the genomic location of choice. The various "knock-in" and "knock-out" modifications can be recovered from the progeny of a single injected animal. The entire process from TALEN design to isolation of DNA-sequence-verified homozygous mutants can be completed in three weeks, and the cost is minimal.