Biology subjects

Voiculescu, O.

Publications and source records attributed to Voiculescu, O..

4 recordsLinked to original sources

bioRxiv2025

DySTrack: a modular smart microscopy tool for live tracking of dynamic samples on modern commercial microscopes

Advances in microscopy and bioimage analysis are enabling unprecedented quantitative observation of dynamic biological systems. Smart microscopy closes the loop by feeding back image-derived information to control image acquisition on the fly, paving the way for increasingly autonomous and sophisticated experiments. However, adoption of smart microscopy remains limited primarily to specialists, and even simple tasks such as live tracking of moving samples are still widely handled manually. Here we describe DySTrack, a modular open-source python tool that serves as a minimal bridge between commercial acquisition software and arbitrary image analysis pipelines, allowing users to stick with familiar vendor-developed user interfaces for microscope configuration whilst leveraging the powerful and platform-agnostic python ecosystem for image analysis. DySTrack comes with detailed documentation and with ready-to-use, easy-to-adapt example pipelines that track moving tissues (namely the zebrafish lateral line primordium and the chick Hensens node) during embryonic development. We hope DySTrack will contribute to a recent push to make smart microscopy more widely accessible.

developmental biology↗

bioRxiv2022

Distinct molecular profile of the chick Organizer as a stem zone during axial elongation

The vertebrate Organizer plays a crucial role in defining the main axes of embryo: it neuralizes the surrounding ectoderm, and is the site of emigration for cells making axial and paraxial mesendoderm during elongation. The chick Organizer becomes a stem zone at the onset of elongation: it stops recruiting cells from the neighbouring ectoderm, and generates all its derivatives from the small number of resident cells it contains at the end of gastrulation stages. Nothing is known about the molecular identity of this stem zone. Here, we specifically labelled long-term resident cells of the Organizer, and compared their RNA-seq profile to that of the neighbouring cell populations. Screening by RT-PCR and in situ hybridisation identified four genes (WIF1, PTGDS, ThPO and UCKL1), which are upregulated only in the Organizer region when it becomes a stem zone, and remain expressed there during axial elongation. In experiments specifically labelling the resident cells of the mature Organizer, we show that only these cells express these genes. These findings molecularly define the Organizer as a stem zone, and offer a key to understanding how this zone is set up, the molecular control of its cells behaviour, and the evolution of axial growth zones.

developmental biology↗

bioRxiv2019

Tissue Mechanics Determines Cell Fate in the Axial Stem Zones

Most embryos and regenerating tissues grow by the action of stem zones. Two epithelial stem zones drive axial elongation in amniotes: the mature organizer generates mesoderm, the neuralised ectoderm around it extends the neuraxis. Bipotential progenitors were also shown to exist. How are these stem cell populations organised and what controls the cell fate of bipotential progenitors? We use direct, in vivo imaging of these stem cells in the chick. We find that progenitors of single and dual fates are mingled in a small region between the specialised stem zones. Divergent tissue movements surround this region. When transplanted downstream of these flows, cells from the region of mixed fates adopt the molecular identity and behaviour of the target stem zone, irrespective of their normal fate. Thus, multipotent cells serve to separate the specialized stem zones, instead of a classical boundary. We propose their fate is determined extrinsically by morphogenetic shearing.

developmental biology↗

bioRxiv2018

The chick caudo-lateral epiblast acts as a permissive niche for generating neuromesodermal progenitor behaviours

Neuromesodermal progenitors (NMps) are a population of bipotent progenitors that maintain competence to generate both spinal cord and paraxial mesoderm throughout the elongation of the posterior body axis. Recent studies have generated populations of NMp-like cells in culture and have been shown to differentiate to both neural and mesodermal cell fates when transplanted into either mouse or chick embryos. Here, we aim to compare the potential of mouse embryonic stem (ES) cell-derived progenitor populations to generate NMp behavior against both undifferentiated and differentiated populations. We define NMp behaviour as the ability of cells to i) contribute to a significant proportion of the anterior-posterior body axis, ii) enter into both posterior neural and somitic compartments and, iii) retain a proportion of the progenitor population within the posterior growth zone. We compare previously identified ES cell-derived NMp-like populations to undifferentiated mouse ES cells and find that they all display similar potentials to generate NMp behaviour in vivo. To assess whether this competence is lost upon further differentiation, we generated anterior and posterior embryonic cell types through the generation of 3D gastruloids and show that NMp competence is lost within the anterior (Brachyury negative) portion of the gastruloid. Taken together, this demonstrates that the chick caudo-lateral epiblast is a highly permissive environment for testing NMp competence and is therefore not suitable as a positive test of neuromesodermal progenitor identity (ie. specification). However, it does act as an appropriate system to test for the loss of NMp potential, and therefore offers insight as a functional test for the regulation of NMp competence in vivo.

developmental biology↗