Biology subjects

Deere, J.

Publications and source records attributed to Deere, J..

4 recordsLinked to original sources

bioRxiv2024

Gut bacteria-derived succinate induces enteric nervous system regeneration

Enteric neurons control gut physiology by regulating peristalsis, nutrient absorption, and secretion1. Disruptions in microbial communities caused by antibiotics or enteric infections result in the loss of enteric neurons and long-term motility disorders2-5. However, the signals and underlying mechanisms of this microbiota-neuron communication are unknown. We studied the effects of microbiota on the recovery of the enteric nervous system after microbial dysbiosis caused by antibiotics. We found that both enteric neurons and glia are lost after antibiotic exposure, but recover when the pre-treatment microbiota is restored. Using murine gnotobiotic models and fecal metabolomics, we identified neurogenic bacterial species and their derived metabolite succinate as sufficient to rescue enteric neurons and glia. Unbiased single-nuclei RNA-seq analysis uncovered a novel neural precursor-like population marked by the expression of the neuronal gene Nav2. Genetic fate-mapping showed that Plp1+ enteric glia differentiate into neurons following antibiotic exposure. In contrast, Nav2+ neurons expand upon succinate treatment and indicate an alternative mode of neuronal regeneration under recovery conditions. Our findings highlight specific microbial species, metabolites, and the underlying cellular mechanisms involved in neuronal regeneration, with potential therapeutic implications for peripheral neuropathies.

neuroscience↗

bioRxiv2023

Calorie restriction brings no benefits to lifespan under stochastic environments

1. Potential immortality is observed in several species (e.g., prickly pear cactus, hydra, flatworms) and is indicative of their negligible or even negative senescence rates. Unlike in senescent species, which experience reduced individual performance with age due to physiological degradation, species with negligible or negative senescence display mortality rates that remain constant or decline with age, respectively. These rates vary across taxa and are correlated with life history traits. Yet, the extent to which variable resource availability, a key driver of variation in life history traits, impacts species that show negligible or negative senescence is currently unknown. 2. Here, we examine whether and how variation in the quantity, quality, and feeding interval of resources impact population structure, population performance, and life history trait trade-offs in two long-lived planaria that do not senesce: Schmidtea mediterranea and Dugesia tahitiensis. In a full factorial design, different combinations of resource quantity (reduced intake, standard intake and high intake) and quality (high and low quality) were provided in two different feeding intervals (7-day and 14-day intervals) for 19 weeks. 3. We show that variability in resource availability, via decreases in quantity, quality, and frequency of resources, does not diminish population viability in either species but does result in suboptimal conditions of stress in S. mediterranea. 4. The high population viability we report can be attributed to two different mechanisms: increased reproduction or increased investment into maintenance at the expense of reproduction. Moreover, which mechanism was responsible for said high population viability was context-dependent and modulated by the specific life history strategy of the two planaria species. 5. We show that suboptimal conditions can cause stress responses that have significant impacts on non-senescent species. The context-dependent response we observe suggests that species that do not senesce but are subject to suboptimal conditions of stress may ultimately exhibit declines in performance and ultimately die. A clearer understanding of the impact of suboptimal conditions of resource availability on non-senescent species is needed to determine the extent of stress experienced and ultimately whether a species can truly be immortal.

ecology↗

bioRxiv2022

MOSAIC: A Unified Trait Database to Complement Structured Population Models

O_LIThe ecological sciences have joined the big data revolution. However, despite exponential growth in data availability, broader interoperability amongst datasets is still needed to unlock the potential of open access. The interface of demography and functional traits is well-positioned to benefit from said interoperability. Trait-based ecological approaches have been criticised because of their inability to predict fitness components, the core of demography; likewise, demographic approaches are data-hungry, and so using traits as ecological shortcuts to understanding and forecasting population viability could offer great value. C_LIO_LIHere, we introduce MOSAIC, an open-access trait database that unlocks the demographic potential stored in the COMADRE, COMPADRE, and PADRINO open-access databases. MOSAIC data have been digitised and curated through a combination of existing datasets and additional taxonomic and/or trait records sourced from primary literature. In its first release, MOSAIC (v. 1.0.0) includes 14 trait fields for 300 animal and plant species: biomass, height, growth determination, regeneration, sexual dimorphism, mating system, hermaphrodism, sequential hermaphrodism, dispersal capacity, type of dispersal, mode of dispersal, dispersal classes, volancy, and aquatic habitat dependency. MOSAIC also includes species-level phylogenies for 1,359 species and population-specific climate data where locations are recorded. C_LIO_LIUsing MOSAIC, we highlight a taxonomic mismatch of widely used trait databases with existing structured population models. Despite millions of trait records available in open-access databases, taxonomic overlap between open-access demographic and trait databases is <5%. We identify where traits of interest to ecologists can benefit from database integration and start to quantify traits that are poorly quantified (e.g., growth determination, modularity). C_LIO_LIThe MOSAIC database evidences the importance of improving interoperability in open-access efforts in ecology as well as the need for complementary digitisation to fill targeted taxonomic gaps. In addition, MOSAIC highlights emerging challenges associated with the disparity between locations where different trait records are sourced. C_LI

ecology↗

bioRxiv2018

A Modelling Exercise to Show Why Population Models Should Incorporate Distinct Life-Histories of Dispersers

Dispersal is an important form of movement influencing population dynamics, species distribution, and gene flow between populations. In population models, dispersal is often included in a simplified manner by removing a random proportion of the population. Many ecologists now argue that models should be formulated at the level of individuals instead of the population-level. To fully understand the effects of dispersal on natural systems, it is therefore necessary to incorporate individual-level differences in dispersal behaviour in population models. Here we parameterised an integral projection model (IPM), which allows for studying how individual life histories determine population-level processes, using bulb mites, Rhizoglyphus robini, to assess to what extent dispersal expression (frequency of individuals in the dispersal stage) and dispersal probability affect the proportion of dispersers and natal population growth rate. We find that allowing for life-history differences between resident phenotypes and disperser phenotypes shows that multiple combinations of dispersal probability and dispersal expression can produce the same proportion of leaving individuals. Additionally, a given proportion of dispersing individuals results in different natal population growth rates. The results highlight that dispersal life histories, and the frequency with which disperser phenotypes occur in the natal population, significantly affect population-level processes. Thus, biological realism of dispersal population models can be increased by incorporating the typically observed life history differences between resident phenotypes and disperser phenotypes, and we here present a methodology to do so.

ecology↗