Biology subjects

Almunia, J.

Publications and source records attributed to Almunia, J..

4 recordsLinked to original sources

bioRxiv2024

Awareness of the future: Dolphins know when they need to remember for the future

In humans, awareness of an upcoming memory test enhances intentional encoding and improves memory recall. Here, we investigated whether dolphins exhibit similar future-oriented encoding of information known to be needed in the future. Dolphins were trained to remember specific, randomly assigned actions for later re-enactment, with either immediate or delayed recall. When an unexpected delay was introduced in trials anticipating immediate recall, memory was retained for only 13 seconds, suggesting working memory encoding. However, when instructed to expect delayed recall, dolphins accurately reproduced actions after delays even after 16 hours. These results suggest that dolphins, anticipating future need, intentionally encode actions to be performed in the future into long-term memory, implying prospective encoding and prospective memory capacities. Their memory also displayed key features of episodic memory: encoding occurred in a single episode, and memory was declarative, as the action itself declared its content. Moreover, dolphins more effectively recalled self-performed actions compared to gestural codifications of the same actions, mirroring the human-typical "enactment effect" and supporting episodic-like memory over semantic memory. Our findings indicate that dolphins show awareness of future memory demands and seem to use a future-oriented, episodic-like memory system, capable of storing prospectively encoded, intended actions in long-term memory.

animal behavior and cognition↗

bioRxiv2022

Age-associated sleep-wake patterns are altered with Prdm13 signaling in the dorsomedial hypothalamus and dietary restriction in mice

Old animals display significant alterations in sleep-wake patterns such as increases in sleep fragmentation and sleep propensity. Here we demonstrated that dorsomedial hypothalamus-specific PR-domain containing protein 13-knockout (DMH-Prdm13-KO) mice recapitulated age-associated sleep alterations such as sleep fragmentation and increased sleep attempts during sleep deprivation (SD). These phenotypes were further exacerbated during aging, with increased adiposity and decreased physical activity, resulting in shortened lifespan. Dietary restriction (DR), a well-known anti-aging intervention in diverse organisms, ameliorated age-associated sleep alterations, whereas these effects of DR were abrogated in DMH-Prdm13-KO mice. Moreover, overexpression of Prdm13 in the DMH ameliorated sleep fragmentation and excessive sleepiness during SD in old mice. Therefore, maintaining Prdm13 signaling in the DMH might play an important role to control sleep-wake patterns during aging.

physiology↗

bioRxiv2021

Universal DNA methylation age across mammalian tissues

Aging is often perceived as a degenerative process resulting from random accrual of cellular damage over time. Despite this, age can be accurately estimated by epigenetic clocks based on DNA methylation profiles from almost any tissue of the body. Since such pan-tissue epigenetic clocks have been successfully developed for several different species, we hypothesized that one can build pan-mammalian clocks that measure age in all mammalian species. To address this, we generated data using 11,754 methylation arrays, each profiling up to 36 thousand cytosines in highly-conserved stretches of DNA, from 59 tissue-types derived from 185 mammalian species. From these methylation profiles, we constructed three age predictors, each with a single mathematical formula, termed universal pan-mammalian clocks that are accurate in estimating the age (r>0.96) of any mammalian tissue. Deviations between epigenetic age and chronological age relate to mortality risk in humans, mutations that affect the somatotropic axis in mice, and caloric restriction. We characterized specific cytosines, whose methylation levels change with age across most mammalian species. These cytosines are greatly enriched in polycomb repressive complex 2-binding sites, are located in regions that gradually lose chromatin accessibility with age and are proximal to genes that play a role in mammalian development, cancer, human obesity, and human longevity. Collectively, these results support the notion that aging is indeed evolutionarily conserved and coupled to developmental processes across all mammalian species - a notion that was long-debated without the benefit of this new compelling evidence. SUMMARYThis study identifies and characterizes evolutionarily conserved cytosines implicated in the aging process across mammals and establishes pan mammalian epigenetic clocks.

developmental biology↗

bioRxiv2020

Using big data to estimate whale watching effort

The growing concerns about the negative effects caused by whale watching on wild The growing concerns about the negative effects caused by whale watching on wild cetacean populations are evincing the need to measure whale watching effort more precisely. The current alternatives do not provide sufficient information or imply time-consuming and staff intensive tasks that limit their effectiveness to establish the maximum carrying capacity for this touristic activity. A methodology based on big data analysis, using Automatic Information System (AIS) messages, can provide valuable vessel activity information, which is necessary to estimate whale watching effort on cetacean populations. We used AIS data to automatically detect whale watching operations and quantify whale watching effort with high spatial and temporal resolution in the Canary Islands. The results obtained in this study are very encouraging, proving that the methodology is able to estimate seasonal and annual trends in the whale watching effort. The methodology has also proved to be effective in providing detailed spatial information about the whale watching effort, which makes an interesting tool to manage spatial regulations and enforce exclusion zones. The widespread use of AIS devices in maritime navigation provides an enormous potential to easily extend this methodology to other regions worldwide. Any public strategy aimed at the sustainable use of the marine resources should enhance the use of this kind of information technologies, collecting and archiving detailed information on the activity of all the vessels, especially in marine protected areas.

ecology↗