Biology subjects

Rose, R. S.

Publications and source records attributed to Rose, R. S..

4 recordsLinked to original sources

bioRxiv2025

Artificial Cells Evidence Apical Compressive Forces Building up During Neuroepithelial Organoid Early Development

During early stages of development of cerebral organoids, budding neuroepithelia display striking changes in size and morphology, occurring very rapidly. Whilst mechanical forces mediated by cadherin-cadherin junctions are known to control the assembly, maturation and stability of epithelia, little is known of the mechanical context associated with neuroepithelial organoid development. In this report, we demonstrate a rapid translocation of YAP to budding neuroepithelial apical junctions, suggesting the build-up of strong compressive forces early on in their development. To study the mechanics of budding rosettes, we designed oil microdroplets stabilised by protein nanosheets displaying cadherin receptors, able to engage with receptors presented by neighbouring neuroepithelial cells, to integrate into embryoid bodies and developing organoids. The resulting artificial cells are able to sustain the formation of mature junctions with neighbouring cells and lead to the recruitment of tight junction maturation proteins such as ZO1. During early budding of neuroepithelial rosettes, artificial cells are found to be rapidly expelled from the developing organoids, further evidencing apical compressive forces. These forces are not opposed by sufficiently strong shear forces from neighbouring cells, or adhesive forces maintaining anchorage to the apical junction, to induce deformation of artificial cells.

bioengineering↗

bioRxiv2022

Enzyme encapsulation peptides bind to the groove between tessellating subunits of the bacterial microcompartment shell

Bacterial microcompartments are prokaryotic organelles consisting of encapsulated enzymes within a thin protein shell. They are involved in metabolic processing including propanediol, choline, glycerol and ethanolamine utilization, and carbon fixation. Enzymes targeted to the inside of the microcompartment frequently possess a cargo-encapsulation peptide, but the binding-site has not been revealed. We provide evidence that the encapsulation peptides bind to the hydrophobic groove formed between tessellating tiles of major shell proteins. In silico docking studies provide a compelling model of peptide binding to this hydrophobic groove. This result is consistent with the now widely accepted view that the convex side of the shell proteins faces the lumen of the microcompartment. Binding between shell protein tiles explains why the encapsulation peptide binding site has been elusive, how encapsulation-peptide bearing enzymes can promote shell assembly, and how the presence of cargo affects the size and shape of the bacterial microcompartment.

biochemistry↗

bioRxiv2020

De Novo Designed Peptide and Protein Hairpins that Self-assemble into Sheets and Nanoparticles.

The design and assembly of peptide based materials has advanced considerably, leading to a variety of fibrous, sheet and nanoparticle structures. A remaining challenge is to account for and control different possible supramolecular outcomes accessible to the same or similar peptide building blocks. Here we present a de novo peptide system that forms nanoparticles or sheets depending on the strategic placement of a disulfide pin between two elements of secondary structure that drive self-assembly. Specifically, we join homodimerizing and homotrimerizing de novo coiled-coil -helices with a flexible linker to generate a series of linear peptides. The helices are pinned back-to-back, constraining them as hairpins by a disulfide bond placed either proximal or distal to the linker. Computational modeling and advanced microscopy show that the proximally pinned hairpins self-assemble into nanoparticles, whereas the distally pinned constructs form sheets. These peptides can be made synthetically or recombinantly to allow both chemical modifications and the introduction of whole protein cargoes as required.

synthetic biology↗

bioRxiv2019

Microbial degradation of plastic in aqueous solutions demonstrated by CO2 evolution and quantification.

The environmental accumulation of plastics worldwide is a consequence of the durability of the material. Alternative polymers, marketed as biodegradable, present a potential solution to mitigate their ecological damage. However, understanding of biodegradability has been hindered by a lack of reproducible testing methods. Here, we present a new approach to assess biodegradability by monitoring bacterial respiration, in an aqueous media supplemented with a polymer as a single carbon source. Rhodococcus rhodochrous and Alcanivorax borkumensis are good model organisms for soil and marine systems respectively, allowing simulations of plastic biodegradation in these key environments. We demonstrate that polymer molecular weight reduction is the critical factor in the biodegradability of low-density polyethylene. Additionally, we tested a wide variety of plastics, including environmentally weathered and laboratory aged samples, using the same method allowing direct comparisons of the relative biodegradability of various polymers.

ecology↗