Biology subjects

Sobrido-Camean, D.

Publications and source records attributed to Sobrido-Camean, D..

8 recordsLinked to original sources

bioRxiv2026

A high-throughput assay quantifies thermal scaling of Drosophila development with minute-scale precision

Precise regulation of developmental timing is essential for coordinated growth and robust development, yet staging remains technically challenging in many model systems. In Drosophila melanogaster, developmental timing has traditionally been assessed using low-throughput or coarse staging methods, limiting insight into how individual larval stages respond to environmental and genetic perturbations. Here, we present a high-throughput, real-time luminometry assay that enables continuous, automated measurement of postembryonic development in individual Drosophila larvae. By monitoring feeding-dependent luciferase activity, this method reliably detects transitions between larval instars and molts of individual larvae with minute-scale temporal resolution. Using this platform, we provide a quantitative, minute-precision, stage-resolved description of larval development across large cohorts, revealing distinct patterns of variability and weak temporal coupling between stages. We next examine how temperature shapes developmental timing across a broad thermal range. Increasing temperature uniformly accelerates larval development while preserving the proportional contribution of each stage, indicating that the temporal architecture of development is maintained as overall pace changes. Developmental rate follows predictable thermodynamic scaling within a defined temperature window, enabling precise estimation of thermal parameters at both whole-organism and stage-specific levels. Finally, we demonstrate that the assay is compatible with genetic perturbations. This work establishes a scalable, high-precision framework for measuring postembryonic development in Drosophila melanogaster. By revealing the modular and coordinated nature of larval growth, it enables systematic dissection of genetic, metabolic, and environmental control of developmental timing and provides a platform to explore fundamental principles of development and robustness across species.

developmental biology↗

bioRxiv2024

Heterogeneous responses to embryonic critical period perturbations among different components of the Drosophila larval locomotor circuit

As developing neural circuits become functional, they undergo a phase of heightened plasticity that facilitates network tuning in response to intrinsic and/or extrinsic stimuli. These developmental windows are termed critical periods (CPs), because perturbations during, but not outside, the CP can lead to lasting changes, such as the formation of sub-optimal or unstable networks. How separate, but connected elements, within a network might respond differently to a CP perturbation is not well understood. To study this, we used the locomotor network of the Drosophila larva as a model and heat stress as a CP stimulus that has ecological relevance. When embryos experienced heat stress the subsequent development of their locomotor network is changed, creating larvae with reduced crawling speed and decreased network stability. Developing body wall muscles and central neurons are sensitive to heat stress perturbations during distinct, consecutive phases of embryogenesis. Within the CNS, transient embryonic CP perturbation leads to increased synaptic drive from premotor interneurons to motoneurons, which in turn adopt reduced excitability. In contrast, the peripheral neuromuscular junction maintains normal synaptic transmission, despite significant structural changes. Thus, connected elements respond differentially to a CP perturbation, suggesting a sequence, or hierarchy, of network adjustment during the CP.

neuroscience↗

bioRxiv2022

Activity-regulated growth of motoneurons at the neuromuscular junction is mediated by NADPH oxidases

Neurons respond to changes in the levels of activity they experience in a variety of ways, including structural changes at pre- and postsynaptic terminals. An essential plasticity signal required for such activity-regulated structural adjustments are reactive oxygen species (ROS). To identify sources of activity-regulated ROS required for structural plasticity in vivo we used the Drosophila larval neuromuscular junction as a highly tractable experimental model system. For adjustments of presynaptic motor terminals, we found a requirement for both NADPH oxidases, Nox and Dual Oxidase (Duox), that are encoded in the Drosophila genome. This contrasts with the postsynaptic dendrites from which Nox is excluded. NADPH oxidases generate ROS to the extracellular space. Here, we show that two aquaporins, Bib and Drip, are necessary ROS conduits in the presynaptic motoneuron for activity regulated, NADPH oxidase dependent changes in presynaptic motoneuron terminal growth. Our data further suggest that different aspects of neuronal activity-regulated structural changes might be regulated by different ROS sources: changes in bouton number require both NADPH oxidases, while activity-regulated changes in the number of active zones might be modulated by other sources of ROS. Overall, our results show NADPH oxidases as important enzymes for mediating activity-regulated plasticity adjustments in neurons.

neuroscience↗

bioRxiv2022

Organization of the corticotropin-releasing hormone and corticotropin-releasing hormone-binding protein systems in the central nervous system of the sea lamprey Petromyzon marinus

The expression of the corticotropin-releasing hormone (PmCRH) and the CRH-binding protein (PmCRHBP) mRNAs was studied by in situ hybridization in the brain of prolarvae, larvae and adults of the sea lamprey Petromyzon marinus. We also generated an antibody against the PmCRH mature peptide to study the distribution of PmCRH-immunoreactive cells and fibers. PmCRH immunohistochemistry was combined with anti-tyrosine hydroxylase immunohistochemistry, PmCRHBP in situ hybridization or neurobiotin transport from the spinal cord. The most numerous PmCRH-expressing cells were observed in the magnocellular preoptic nucleus-paraventricular nucleus and in the superior and medial rhombencephalic reticular formation. PmCRH expression was more extended in adults than in larvae, and some cell populations were mainly (olfactory bulb) or only (striatum, ventral hypothalamus, prethalamus) observed in adults. The preopto-paraventricular fibers form conspicuous tracts coursing towards the neurohypophysis, but many immunoreactive fibers were also observed coursing in many other brain regions. Brain descending fibers in the spinal cord come from cells located in the isthmus and in the medial rhombencephalic reticular nucleus. The distribution of PmCRHBP-expressing neurons was different from that of PmCRH cells, with cells mainly present in the septum, striatum, preoptic region, tuberal hypothalamus, pretectum, pineal complex, isthmus, reticular formation, and spinal cord. Again, expression in adults was more extended than in larvae. PmCRH- and PmCRHBP-expressing cells are different, excluding colocalization of these substances in the same neuron. Present findings reveal a complex CRH/CRHBP system in the brain of the oldest extant vertebrate group, the agnathans, which shows similarities but important divergences with that of mammals.

neuroscience↗

bioRxiv2022

Reconstructing the ancestral vertebrate brain using a lamprey neural cell type atlas

The vertebrate brain emerged more than [~]500 million years ago in common evolutionary ancestors. To systematically trace its cellular and molecular origins, we established a spatially resolved cell type atlas of the entire brain of the sea lamprey - a jawless species whose phylogenetic position affords the reconstruction of ancestral vertebrate traits - based on extensive single-cell RNA-seq and in situ sequencing data. Comparisons of this atlas to neural data from the mouse and other jawed vertebrates unveiled various shared features that enabled the reconstruction of the core cell type composition, tissue structures, and gene expression programs of the ancestral brain. However, our analyses also revealed key tissues and cell types that arose later in evolution. For example, the ancestral vertebrate brain was likely devoid of cerebellar cell types and oligodendrocytes (myelinating cells); our data suggest that the latter emerged from astrocyte-like evolutionary precursors on the jawed vertebrate lineage. Our work illuminates the cellular and molecular architecture of the ancestral vertebrate brain and provides a foundation for exploring its diversification during evolution.

evolutionary biology↗

bioRxiv2019

Differential expression of five prosomatostatin genes in the central nervous system of the catshark Scyliorhinus canicula

Five prosomatostatin genes (PSST1, PSST2, PSST3, PSST5 and PSST6) have been recently identified in elasmobranchs (Tostivint, Gaillard, Mazan, & Pezeron, 2019). In order to gain insight into the contribution of each somatostatin to specific nervous systems circuits and behaviors in this important jawed vertebrate group, we studied the distribution of neurons expressing PSST mRNAs in the catshark Scyliorhinus canicula using in situ hybridization with specific probes for the five PSSTs transcripts. Additionally, we combined in situ hybridization with tyrosine hydroxylase (TH) immunochemistry for better localization of some PSSTs-positive populations. The five PSST genes showed expression in the brain, although with important differences in distribution. PSST1 and PSST6 were widely expressed in different brain regions. Instead, PSST2 and PSST3 were expressed only in the ventral hypothalamus and in some hindbrain lateral reticular neurons, whereas PSST5 was only expressed in the region of the entopeduncular nucleus. PSST1 and PSST6 were expressed by numerous pallial neurons, although in different populations judging from the colocalization of tyrosine hydroxylase (TH) immunoreactivity and PSST6 expression in pallial neurons and the absence of colocalization between TH and PSST1 expression. Differential expression of PSST1 and PSST6 was also observed in the subpallium, hypothalamus, diencephalon, optic tectum, midbrain tegmentum and rhombencephalon. Expression of PSST1 was observed in numerous cerebrospinal fluid-contacting (CSF-c) neurons of the paraventricular organ of the hypothalamus and the central canal of the spinal cord. These wide differences in expression of PSST genes together with the numerous brain nuclei expressing PSSTs, indicate that catshark somatostatinergic neurons are implicated differentially in a number of neural circuits.

neuroscience↗

bioRxiv2019

Taurine promotes axonal regeneration after a complete spinal cord injury in lampreys

Taurine is one of the most abundant free amino acids in the brain. It is well known that taurine protects the brain from further damage after a traumatic event. However, only a few ex vivo studies have looked at the possible role of taurine in the regulation of axon regeneration after injury. Here, we aimed to reveal the possible role for taurine in the modulation of axonal regeneration following a complete spinal cord injury (SCI) using lampreys as an animal model. The brainstem of lampreys contains several individually identifiable descending neurons that differ greatly in their capacity for axonal regeneration after SCI. This offers a convenient model to promote or inhibit axonal regrowth in the same in vivo preparation. First, we carried out high performance liquid chromatography experiments to measure taurine levels in the spinal cord following SCI. Our results revealed a statistically significant increase in taurine levels 4 weeks post lesion, which suggested that taurine might have a positive effect on axonal regrowth. Based on these results, we decided to apply an acute taurine treatment at the site of injury to study its effect on axon regeneration. Results from these experiments show that an acute taurine treatment enhances axonal regeneration following SCI in lampreys. This offers a novel way to try to promote axon regeneration after nervous system injuries in mammalian models.

neuroscience↗

bioRxiv2018

Serotonin inhibits axonal regeneration of identifiable descending neurons after a complete spinal cord injury in lampreys

Classical neurotransmitters are mainly known for their roles as neuromodulators, but they also play important roles in the control of developmental and regenerative processes. Here, we used the lamprey model of spinal cord injury to study the effect of serotonin in axon regeneration at the level of individually identifiable descending neurons. Pharmacological and genetic treatments after a complete spinal cord injury showed that endogenous serotonin inhibits axonal regeneration in identifiable descending neurons through the activation of serotonin 1A receptors and a subsequent decrease in cAMP levels. RNA sequencing revealed that changes in the expression of genes that control axonal guidance could be a key factor on the serotonin effects during regeneration. This study provides new targets of interest for research in non-regenerating mammalian models of traumatic CNS injuries and extends the known roles of serotonin signalling during neuronal regeneration.

neuroscience↗