Single-neuron analysis of aging-associated changes in learning reveals impairments in transcriptional plasticity.

The molecular mechanisms underlying age-related declines in learning and long-term memory are still not fully understood. To address this gap, our study focused on investigating the transcriptional landscape of a singularly identified motor neuron L7 in Aplysia, which is pivotal in a specific type of nonassociative learning known as sensitization of the siphon-withdraw reflex. Employing total RNAseq analysis on a single isolated L7 motor neuron after short-term or long-term sensitization (LTS) training of Aplysia at 8, 10, and 12 months (representing mature, late mature, and senescent stages), we uncovered aberrant changes in transcriptional plasticity during the aging process.

Temperature effects on growth, maturation, and lifespan of the california sea hare (Aplysia californica).

We conducted a hatchery growth study to describe the variability in growth rates, spawning, and mortality of Aplysia californica in regard to rearing temperature. Animals were housed at a standard hatchery density of five animals per cage, at temperatures of 13, 15, 18, and 21 degrees Celsius. Animals reared at 13 or 15 degrees C grew as much as four times as large, lived twice as long, matured later, and spawned longer than did animals reared at 18 or 21 degrees C.

Reproductive output in the hatchery-reared california sea hare at different stocking densities.

Although the California sea hare (Aplysia californica) is well known from neurobiological studies and is raised in the laboratory for this purpose, the life history of this species in the laboratory is less well studied. Therefore we conducted a study of the reproductive period of hatchery-born and -raised A. californica in which sibling animals were reared at stocking densities of 2, 5, 10, 15, and 20 animals per 16-liter cage.

The effect of stocking density on growth rate and maturation time in laboratory-reared california sea hares.

California sea hares (Aplysia californica) were reared from the late juvenile period (approximately day 100 posthatch) to senescence in a laboratory study of growth and maturation at different stocking densities. Temperature, light, and food were controlled, and other seawater parameters such as O2 concentration, pH, and salinity, although not controlled, were optimized by the flow-through design of seawater through the cages. Stocking densities evaluated were 1, 2, 5, 10, 15, and 20 animals per 16-liter cage.