Biology subjects

Peru, E.

Publications and source records attributed to Peru, E..

3 recordsLinked to original sources

bioRxiv2026

Time in shells: Complex interaction between biological clock and biomineralisation in Mytilus galloprovincialis

The growth of bivalve shells is neither homogeneous nor continuous in time, resulting in the formation of growth patterns that correspond to the alternation of growth lines and increments deposited at regular intervals of time. The control of periodic increment formation is poorly understood and several hypotheses have been proposed. It has been proposed that environmental factors directly impact shell growth patterns, although it occasionally fails to adequately explain the observed shell growth patterns. The present study investigates the alternative hypothesis that the process of shell biomineralisation is controlled by biological clocks. This study demonstrates the existence of a functional circadian clock in M. galloprovincialis, as evidenced by molecular and behavioural results. Core circadian clock genes and biomineralisation genes have been observed to be expressed in the same cells of the mantle as revealed by in situ hybridisation experiments. However, the expression of core circadian clock genes and biomineralisation genes tested in situ and in aquaria exhibited different rhythmic profiles. This finding suggests that the clock does not directly activate the expression of the targeted biomineralisation genes in the mantle. Nevertheless, a significant rhythm of expression of biomineralisation-related genes was observed in mussels reared under free-running conditions, revealing the endogenous nature of the rhythm. The present study suggests that biological clocks play a role in controlling shell biomineralisation in M. galloprovincialis, although the precise underlying mechanism remains to be elucidated.

physiology↗

bioRxiv2024

Chemoarchitectural studies of the rat hypothalamus and zona incerta.Chemopleth 1.0, a downloadable interactive Brain Maps spatial database of five co-visualizable neurochemical systems, with novel feature- and grid-based mapping tools

The hypothalamus and zona incerta of the brown rat (Rattus norvegicus), a model organism important for translational neuroscience research, contain diverse neuronal populations essential for survival, but how these populations are structurally organized as systems remains elusive. With the advent of novel gene-editing technologies and artificial intelligence, there is an apparent research need for high-spatial-resolution maps of rat hypothalamic neurochemical cell types to aid in their gene-directed targeting, to validate their expression in transgenic lines, or to supply precious ground-truth training data for machine learning algorithms. Here, we present Chemopleth 1.0 [available at: https://doi.org/10.5281/zenodo.15788189], a chemoarchitecture database for the rat hypothalamus (HY) and zona incerta (ZI), which features downloadable interactive maps featuring the census distributions of five immunoreactive neurochemical systems: (1) vasopressin (as detected from its gene co-product, copeptin); (2) neuronal nitric oxide synthase (EC 1.14.13.39); (3) hypocretin 1/orexin A; (4) melanin-concentrating hormone; and (5) alpha-melanocyte-stimulating hormone. These maps are formatted for the widely used Brain Maps 4.0 (BM4.0) open-access rat brain atlas (RRID:SCR_017314). Importantly, this dataset retains atlas stereotaxic coordinates that facilitate the precise targeting of the cell bodies and/or axonal fibers of these neurochemical systems, thereby potentially serving to streamline delivery of viral vectors for gene-directed manipulations. The maps are presented together with novel open-access tools to visualize the data, including a new workflow to quantify cell positions and fiber densities for BM4.0. The workflow produces "heat maps" of neurochemical distributions from multiple subjects: 1) isopleth maps that represent consensus distributions independent of underlying atlas boundary conditions, and 2) choropleth maps that provide distribution differences based on cytoarchitectonic boundaries. The database files, generated using the Adobe(R) Illustrator(R) vector graphics environment, can also be opened using the free vector graphics editor, Inkscape. We also introduce a refined grid-based coordinate system for this dataset, register it with previously published spatial data for the HY and ZI, and introduce novel grid-based annotation of experimental observations. This database provides critical spatial targeting information for these neurochemical systems unavailable from mRNA-based maps and allows readers to place their own datasets in register with them. It also provides a space for the continued buildout of a community-driven atlas-based spatial model of rat hypothalamic chemoarchitecture, allowing experimental observations from multiple laboratories to be registered to a common spatial framework.

neuroscience↗

bioRxiv2022

Contributions of Gonadal Hormones in the Sex-Specific Organization of Context Fear Learning

It is widely established that gonadal hormones are fundamental to modulating and organizing the sex-specific nature of reproductive-related behaviors. Recently we proposed that context fear conditioning may emerge in a sex-specific manner organized prior to the pubertal surge of gonadal hormones. Here we sought to determine the necessity of male and female gonadal hormones secreted at critical periods of development upon context fear learning. We tested the organizational hypothesis that perinatal and pubertal gonadal hormones play a permanent role in organizing contextual fear learning. We demonstrate that the life-long absence of gonadal hormones by perinatal orchiectomy (oRX) in males and ovariectomy (oVX) in females resulted in a reduction of CFC in adult males and an enhancement of CFC in adult females. In females, the gradual introduction of estrogen before conditioning partially rescued this effect. However, the decrease of CFC in adult males was not rescued by introducing testosterone before conditioning. Next, at a further point in development, preventing the pubertal surge of gonadal hormones by prepubertal oRX in males resulted in a reduction in adult CFC. In contrast, in females, prepubertal oVX did not alter adult CFC. However, the adult introduction of estrogen in prepubertal oVX rats reduced adult CFC. Lastly, the adult-specific deletion of gonadal hormones by adult oRX or oVX alone or replacement of testosterone or estrogen did not alter CFC. Consistent with our hypothesis, we provide initial evidence that gonadal hormones at early periods of development exert a vital role in the organization and development of CFC in male and female rats.

animal behavior and cognition↗