Biology subjects

Adelmann, L.

Publications and source records attributed to Adelmann, L..

3 recordsLinked to original sources

bioRxiv2024

Molecular profile, source and lineage restriction of stem cells in an annelid regeneration model

Regeneration of missing body parts can be observed in diverse animal phyla, but it remains unclear to which extent these capacities rely on shared or divergent principles. Research into this question requires detailed knowledge about the involved molecular and cellular principles in suitable reference models. By combining single-cell RNA sequencing and mosaic transgenesis in the marine annelid Platynereis dumerilii, we map cellular profiles and lineage restrictions during posterior regeneration. Our data reveal cell-type specific injury responses, re-expression of positional identity factors, and the re-emergence of stem cell signatures in multiple cell populations. Epidermis and mesodermal coelomic tissue produce distinct putative posterior stem cells (PSCs) in the emerging blastema. A novel mosaic transgenesis strategy reveals both developmental compartments and lineage restrictions during regenerative growth. Our work supports the notion that posterior regeneration involves dedifferentiation, and reveals molecular and mechanistic parallels between annelid and vertebrate regeneration.

developmental biology↗

bioRxiv2024

Elongation capacity of polyunsaturated fatty acids in the annelid Platynereis dumerilii

In animals, elongation of very long-chain fatty acid (Elovl) proteins play pivotal functions in the biosynthesis of fatty acids, including the physiologically essential long-chain polyunsaturated fatty acids (LC-PUFA). Polychaetes have important roles in marine ecosystems, contributing not only to nutrient recycling but also exhibiting a distinctive capacity for biosynthesising LC-PUFA, as emphasised in previous research. In order to expand our current understanding of the LC-PUFA biosynthesis in polychaetes, the present study conducted a thorough molecular and functional characterisation of Elovl occurring in the model organism Platynereis dumerilii. In this study, we identify six Elovl proteins in the genome of P. dumerilii. The sequence and phylogenetic analyses established that four Elovl, identified as Elovl2/5, Elovl4 (two genes) and Elovl1/7, have putative functions in the LC-PUFA biosynthesis. Functional characterisation in yeast confirmed the roles of these elongases in the LC-PUFA biosynthetic pathways, demonstrating that P. dumerilii possesses a varied and functionally diverse complement of Elovl enzymes that, along the enzymatic specificities of previously characterised desaturases, enable P. dumerilii to perform all the reactions required for the biosynthesis of the LC-PUFA. Importantly, we uncovered that one of the two Elovl4-encoding genes from P. dumerilii is remarkably long in comparison with any other animals Elovl, which contains a C terminal KH domain unique among Elovl enzymes. The distinctive expression pattern of this protein in photoreceptors strongly suggests a central role in vision.

biochemistry↗

bioRxiv2018

Enhanced in vivo-imaging in fish by optimized anaesthesia, fluorescent protein selection and removal of pigmentation

Fish are ideally suited for in vivo-imaging due to their transparency at early stages combined with a large genetic toolbox. Key challenges to further advance imaging are fluorophore selection, immobilization of the specimen and approaches to eliminate pigmentation.\n\nWe addressed all three and identified the fluorophores and anaesthesia of choice by high throughput time-lapse imaging. Our results indicate that eGFP and mCherry are the best conservative choices for in vivo-fluorescence experiments, when availability of well-established antibodies and nanobodies matters. Still, mVenusNB and mGFPmut2 delivered highest absolute fluorescence intensities in vivo. Immobilization is of key importance during extended in vivo imaging. Here, traditional approaches are outperformed by mRNA injection of -Bungarotoxin which allows a complete and reversible, transient immobilization. In combination with fully transparent juvenile and adult fish established by the targeted inactivation of both, oca2 and pnp4a via CRISPR/Cas9-mediated gene editing in medaka we could dramatically improve the state-of-the art imaging conditions in post-embryonic fish, now enabling light-sheet microscopy of the growing retina, brain, gills and inner organs in the absence of side effects caused by anaesthetic drugs or pigmentation.

developmental biology↗