The effect of brumation on memory retention

Adaptive management in a conservation breeding program: Mimicking habitat complexities facilitates reproductive success in narrow-headed gartersnakes (Thamnophis rufipunctatus)

Mimicking natural parameters and complexities in zoo conservation breeding programs can facilitate natural physiological and behavioral traits, which in turn can inform more effective species reintroduction efforts. To curtail population declines of threatened narrow-headed gartersnakes (Thamnophis rufipunctatus), the Arizona Center for Nature Conservation/Phoenix Zoo partnered with a multiagency conservation working group to develop an ex situ propagation-for-release program. Initially, Zoo staff followed common snake husbandry protocols of manually inducing brumation (i.e., winter dormancy). Copulation was observed during the first few years, but no births resulted. Also, some older individuals developed post-brumation health abnormalities, prompting a strategic reassessment. To facilitate propagation and improve health, Zoo staff applied ecological knowledge of T. rufipunctatus and an adaptive management strategy to implement key parameters for success: sociality, refugia, breeding and foraging behaviors, and natural brumation. Zoo staff developed a large multisnake enclosure that mimicked natural ecological and habitat complexities including a hibernaculum to stimulate natural brumation. Gartersnakes were left mostly unimpeded to conduct natural behaviors across seasons in the enriched environment. We referenced change in body mass after ten brumation periods as a proxy for health. Under natural brumation, gartersnakes did not lose body mass, and this shift resulted in fully ex situ parturition events-the first for this imperiled species. We highlight the efficacy of adaptive management and incorporation of natural parameters and environmental complexities into conservation breeding programs. These actions can improve the health and success of animals under managed care-processes applicable to a range of taxa targeted for conservation translocations.

Polyaneuploid Cancer Cell Dormancy: Lessons From Evolutionary Phyla

Dormancy is a key survival strategy in many organisms across the tree of life. Organisms that utilize some type of dormancy (hibernation, aestivation, brumation, diapause, and quiescence) are able to survive in habitats that would otherwise be uninhabitable. Induction into dormant states is typically caused by environmental stress. While organisms are dormant, their physical activity is minimal, and their metabolic rates are severely depressed (hypometabolism). These metabolic reductions allow for the conservation and distribution of energy while conditions in the environment are poor. When conditions are more favorable, the organisms are then able to come out of dormancy and reengage in their environment. Polyaneuploid cancer cells (PACCs), proposed mediators of cancer metastasis and resistance, access evolutionary programs and employ dormancy as a survival mechanism in response to stress. Quiescence, the type of dormancy observed in PACCs, allows these cells the ability to survive stressful conditions (e.g., hypoxia in the microenvironment, transiting the bloodstream during metastasis, and exposure to chemotherapy) by downregulating and altering metabolic function, but then increasing metabolic activities again once stress has passed. We can gain insights regarding the mechanisms underlying PACC dormancy by looking to the evolution of dormancy in different organisms.

Aversive conditioning in the tardigrade, Dactylobiotus dispar

Defensive responses to threatening events in the environment are displayed by a vast number of animals, both vertebrate and invertebrate. These defensive responses can be associated with salient neutral stimuli that are present along with the threatening stimulus. This is referred to as aversive conditioning. Animals with more simple nervous systems, such as Aplysia, C elegans, and Drosophila, have facilitated identification of some the physiological processes that support aversive conditioning. Perhaps even more basic information regarding the neurobiology of learning and memory may be gleaned from animals that have special characteristics not found in other species. Tardigrades, also known as "water bears," are microscopic eight-legged animals that live in various aquatic and terrestrial environments. They are known for their resilience to extreme conditions because of their ability to enter a cryptobiotic "tun" state during which they turn off their metabolism. Thus, tardigrades present an ideal model to study the metabolic requirements for memory storage. However, there is no prior research on tardigrade learning and memory. The purpose of this study was to demonstrate aversive conditioning in a tardigrade species, Dactylobiotus dispar. Associative learning was confirmed by numerous control conditions (unconditioned stimulus [US] only, conditional stimulus [CS] only, backward pairing, random pairing). Short-term memories were formed after a single pairing of the CS and US. This research introduces an important new animal model to the study of the neurobiology of aversive conditioning with important ramifications for understanding the metabolic influences on learning and memory. (PsycINFO Database Record (c) 2019 APA, all rights reserved).