DNA damage modulates sleep drive in basal cnidarians with divergent chronotypes
TL;DR
Imagine your nerve cells are tiny workers in a factory that runs all day. As they work, they make a small mess and sometimes break their tools (this is like DNA damage). Sleep is like the night-time cleaning and repair crew. It shuts down the main factory operations so the crew can come in, clean up the mess, and fix the broken tools. This study looked at the simplest, oldest factories in the animal kingdom—jellyfish and sea anemones—and found that they also need this nightly repair crew. When they were forced to stay 'awake,' the mess and broken tools piled up. This suggests that the need for a dedicated repair shift (sleep) is a very old and essential part of being an animal.
Sleep is a conserved behavior across all animals with a nervous system, ranging from cnidarians to humans. Considering the survival risks, why sleep evolved in basal lineages and what essential benefits it provides to the simple nerve net of nocturnal and diurnal invertebrates remain elusive. We used behavioral criteria to empirically define sleep in the upside-down jellyfish Cassiopea andromeda and the starlet sea anemone Nematostella vectensis. Light and homeostasis were the primary drivers of sleep in C. andromeda, which slept at night and napped at midday in both the laboratory and the natural habitat. In contrast, both the circadian clock and homeostatic processes regulated sleep in N. vectensis, which increased sleep at dawn. Similar to humans, C. andromeda, wild-type (WT) and Clock mutant (NvClkΔ/Δ) N. vectensis slept about one-third of the day, irrespective of the daily timing and architecture of sleep, and melatonin promoted sleep in accordance with the species-specific chronotype. Notably, sleep deprivation, ultraviolet radiation, and mutagens increased neuronal DNA damage and sleep pressure, while spontaneous and induced sleep facilitated genome stability in both the diurnal and crepuscular cnidarians. These results suggest that DNA damage and cellular stress in simple nerve nets may have driven the evolution of sleep.
- 1Sleep in Cassiopea andromeda is primarily driven by light and homeostasis, while in Nematostella vectensis, it is regulated by the circadian clock and homeostatic processes.
- 2Both species sleep about one-third of the day, similar to humans, and melatonin promotes sleep according to species-specific chronotypes.
- 3Sleep deprivation, UV radiation, and mutagens increase neuronal DNA damage and sleep pressure, while sleep facilitates genome stability.
- 4The study suggests that DNA damage and cellular stress in simple nerve nets may have driven the evolution of sleep.
Adversarial AI reveals mechanisms and treatments for disorders of consciousness
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Gene conversion empowers natural selection in a clonal fish species
Unfortunately, the content of this research abstract could not be accessed due to paywall restrictions. Without being able to read the actual findings about gene conversion in clonal fish species, I cannot provide an accurate explanation of what the researchers discovered or why it matters.
Direct detection of an asteroid’s heliocentric deflection: The Didymos system after DART
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The dynamics of AMPA receptors underlies the efficacy of ketamine in treatment resistant patients with depression
Think of your brain as having billions of tiny locks and keys. One particular lock — called the AMPA receptor — sits on brain cells and helps them talk to each other using the chemical glutamate. In people with hard-to-treat depression, this study found that those locks are less plentiful than normal, especially in emotional brain regions. When doctors gave these patients ketamine, it actually changed how many of those locks were available on the cell surface — and the bigger that change was, the better the patient felt. So ketamine isn't just temporarily numbing pain; it appears to be physically restoring a broken communication system in the brain. The scientists confirmed this by using a special brain scan (PET scan) with a radioactive tracer that literally glows where those AMPA receptor locks are located, letting them count them in real time in living people.