Food-deprivation inhibits the stress-induced sleep response in C. elegans.
For many animals, the essential physiological drives of sleep and food are intimately linked. You might have noticed this if you’ve ever stayed up far too late and found yourself craving a snack. Yet because it’s impossible for most animals to eat and sleep at the same time, these two biological necessities must compete with each other. In GENETICS, Goetting et al. report what happens when the need for sleep and the need for food come into direct conflict in the model nematode Caenorhabditis elegans.
When C. elegans is exposed to a stressful condition like high heat or UV radiation, it goes into a quiescent state called stress-induced sleep (SIS). Sleeping worms cease moving and feeding, and they barely respond to normally unpleasant stimuli—unless they are rudely awoken by a sharp poke.
In contrast, the authors found that food-deprived worms were less prone to this stress-induced snooze than their well-fed counterparts. This was true regardless of whether there was more food around to forage for; that is, the worms tended to remain active after stress whether or not they were provided with additional food after being starved.
The authors also found that starvation-induced sleep-suppression was enhanced when there were more worms on the plate. This makes sense, because higher population densities mean fewer resources, so seeking food instead of going to sleep is likely the better option. Interestingly, crowding only inhibited SIS when worms were starved; well-fed worms in crowded plates showed no change in SIS after stress treatment.
Insulin signaling and TGF-β signaling play major roles in sensing food availability in C. elegans, so the authors asked whether these pathways play a role in SIS under normal conditions. They found that worms with mutations in a TGF-β ligand, but not the insulin receptor, had impairments in SIS. Further investigation revealed that TGF-β involvement in SIS is downstream of the ALA neuron (a master neural regulator of SIS) and dependent on the gene DAF-3, which is involved in TGF-β signaling.
If this DAF-3-dependent pathway was necessary and sufficient for food-deprivation-induced inhibition of SIS, it would follow that worms lacking DAF-3 would have no trouble falling asleep after being starved and stressed—but when the authors tested this, they instead found that the DAF-3 mutants had the same response as wild-types: they stayed awake. Therefore, the authors conclude that although the TGF-β pathway plays a role in normal SIS, it is not solely responsible for the lack of SIS when worms are starved. Consistent with this notion, the authors uncovered evidence that the TOR signaling pathway, which is active when nutrients are available and promotes growth and protein synthesis, plays a role in starvation-induced sleep suppression as well.
Since sleep deprivation can be deadly, the authors tested whether food deprivation affected how much the worms needed to sleep to stay alive. They found that worms that were deprived of food, stressed, and then kept awake survived better than worms that were just stressed and kept awake. Thus, starving the worms allowed them to stay awake, at least in part, because they needed their sleep less.
CITATION:
Food-Dependent Plasticity in Caenorhabditis elegans Stress-Induced Sleep Is Mediated by TOR–FOXA and TGF-b Signaling
Science Writing and Communications Intern, Genetics Society of America.
View all posts by Marisa Wexler »Read more in
-
In Memoriam: Ellsworth Herman Grell (1932–2023), a pioneer of Drosophila genome engineering and annotation
Ellsworth (Ed) Grell blessed the Drosophila community through three enduring legacies: as a pioneer of chromosome mechanics, as a primary organizer and synthesizer of genetic knowledge in Drosophila, and as a graceful mentor to those fortunate to have known him personally. Ed grew up in rural Nebraska, completed his undergraduate studies at Iowa State, and…
-
Congratulations to the #Fungal24 Poster Award winners!
We are pleased to announce the recipients of the GSA Poster Awards for posters presented at the 32nd Fungal Genetics Conference! Undergraduate and graduate student members of GSA were eligible for the awards, and a hard-working team of judges made the determinations. Congratulations to all! Felicia Ebot Ojong, The University of Georgia My research is focused…
-
Poster presentation tips for TAGC 2024
You’ve been selected to present a poster at The Allied Genetics Conference 2024 in March—you’ve celebrated, made plans to attend, now what? This is an exciting opportunity to showcase your research and engage with fellow members of the genetics community, so you want to make sure you’re prepared. We wanted to offer you some tips…
-
Maximize your TAGC 2024 experience
A guide to all that National Harbor & DC have to offer Are you joining us for The Allied Genetics Conference 2024 in March? Make the most of your #TAGC24 experience in National Harbor! We know the science will keep you busy, but you deserve to unwind and have some fun, so we’ve curated a…
-
Early Career Leadership Spotlight: Sarah Petrosky
We’re taking time to get to know the members of the GSA’s Early Career Scientist Committees. Join us to learn more about our early career scientist advocates. Sarah PetroskyMultimedia SubcommitteeUniversity of Pittsburgh Research Interest I am interested in understanding adaptation that has been happening recently in populations by dissecting the ways that genes underlying an adaptation…
-
TAGC 2024 Early Career Award Winners
GSA is pleased to announce the winners of the early career awards presented at The Allied Genetics Conference 2024. These awards are specific to particular TAGC communities and recognize early career scientists’ outstanding work on their respective research organisms. The awardees will present their talks in keynote sessions at TAGC 2024. Don’t miss the opportunity…
-
Preeminent geneticists recognized with revamped GSA Awards
In 2022, GSA’s Board of Directors launched an audit to review the five major awards conferred by the Society. Today, we are thrilled to announce the recipients of the reimagined GSA Awards, including the new Genetics Society of America Early Career Medal. The scientists honored this year are recognized by their peers for their outstanding…
-
Fly Board funds outreach programs to spread the word about Drosophila research
In 2020, the Fly Board voted to use part of its reserve fund to support efforts to increase trainee participation as well as equity and diversity in the Drosophila community. An awards committee decides how the money will be spent each year, and from 2020–2022, the committee posted a very broad call for applications from…
-
New members of the GSA Board of Directors: 2024–2026
We are pleased to announce the election of four new leaders to the GSA Board of Directors: 2024 Vice President/2025 President Brenda Andrews Professor, University of Toronto It’s an honor to continue my association with the Society by serving as Vice President of the Board of Directors. I have broad knowledge of the ongoing activities…
-
Parrot plumage study aids breeders and endangered natural populations
Yellow coloration is maladaptive in the wild but prized by breeders. People have long been fascinated with birds, which exhibit one of the widest ranges of coloration among vertebrates. Parrots, in particular, have captivated humans by their ability to mimic human speech and spectacular plumage. Brightly colored feathers are used primarily to attract mates, intimidate…
-
Early Career Leadership Spotlight: Sarah Gilmour
We’re taking time to get to know the members of the GSA’s Early Career Scientist Committees. Join us to learn more about our early career scientist advocates. Sarah GilmourMultimedia SubcommitteeStowers Institute for Medical Research Research Interest Questions of evolution have always fascinated me. I am extremely fortunate to be starting out my research career in a…