Biology subjects

Romero-Brey, I.

Publications and source records attributed to Romero-Brey, I..

4 recordsLinked to original sources

bioRxiv2026

An Advanced Mobile Laboratory to enable field-based microbial ecology and cell biology across scales

Microbial biodiversity is central to ecosystem function, yet mechanistic insights into the cell biology of environmental organisms remain limited. The underlying challenges are twofold: most microbes remain uncultivable, and a persistent gap exists between field sampling and laboratory analyses. Here, we introduce the Advanced Mobile Laboratory (AML), a field-deployable platform that integrates confocal microscopy, image-enabled cell sorting, and cryo-preparation for expansion and electron microscopy. This setup enables immediate, standardized processing and analysis of environmental communities directly at the sampling site. We demonstrate its capability using marine eukaryotic plankton, showing how the AML enables multiscale investigations, from live imaging of natural communities to enabling ultrastructural and single-cell omics analyses, while minimizing sample degradation and enabling on-site experimentation. By bringing high-end sample preparation and analytical capacity into the field, the AML enables studying life in its natural context to mechanistically understand lifes diversity in the environment.

cell biology↗

bioRxiv2025

Diatom ultrastructural diversity across controlled and natural environments

Diatoms are ubiquitous aquatic microalgae critical to our planet, that were amongst the pioneer model organisms in cell biology for their large and transparent cell structure. However, their robust silica cell wall renders diatoms impermeable to many dyes and antibodies, and complicates the intracellular delivery of gene editing tools - driving in part the eventual decline of diatoms as mainstream model species despite their unique cellular physiology and remarkable ecological success. Here, we demonstrate that cryo-fixation combined with ultrastructural expansion microscopy (cryo-ExM) can overcome the silica barrier across diverse diatom species spanning over 80 million years of evolutionary time. We illustrate the potential of cryo-ExM to provide scalable, cost-effective volumetric imaging of diatom ultrastructure in laboratory cultures, as well as field-collected samples from the pan-European TREC expedition. We first reveal striking similarities in interphase microtubule organization across diverse diatom species by characterizing cytoskeletal arrangements throughout cell cycles and populations, uniting both pennate and centric morphologies under shared principles. We further unveil diatom photosynthetic diversity through qualitative and quantitative comparative analysis of chloroplast and pyrenoid morphologies, demonstrating that each diatom species architects unique photosynthetic machinery. Using cryo-ExM on environmental samples further exposes intricate diatom symbioses, revealing tight spatial organisation of ecological interactions. This methodology makes diatoms more accessible for modern and comparative cell biology research, providing new opportunities to investigate the cellular mechanisms of one of Earths most successful photosynthetic groups. HighlightsO_LICryo-ExM successfully overcomes diatom frustule barriers to achieve consistent, high-resolution immunofluorescence across evolutionarily diverse species - allowing for comparative cell biology in one of the most important phytoplankton groups on the planet. C_LIO_LICharacterizing microtubule organisation in asynchronously cycling single cells and colonial chains, reveals core features of interphase microtubule organisation across multiple pennate and centric diatom species. C_LIO_LIComparative analysis of chloroplast and pyrenoid morphologies across species provides qualitative and quantitative insights on photosynthetic diversity, suggesting that photosynthetic architectures are unique to each diatom. C_LIO_LIApplied to environmental samples, cryo-ExM provides detailed insight on spatial organisation of diatom symbioses. C_LI

cell biology↗

bioRxiv2022

Crosshair, semi-automated targeting for electron microscopy with a motorised ultramicrotome

Volume electron microscopy (EM) is a time consuming process - often requiring weeks or months of continuous acquisition for large samples. In order to compare the ultrastructure of a number of individuals or conditions, acquisition times must therefore be reduced. For resin-embedded samples, one solution is to selectively target smaller regions of interest by trimming with an ultramicrotome. This is a difficult and labour-intensive process, requiring manual positioning of the diamond knife and sample, and much time and training to master. Here, we have developed a semi-automated workflow for targeting with a modified ultramicrotome. We adapted two recent commercial systems to add motors for each rotational axis (and also each translational axis for one system), allowing precise and automated movement. We also developed a user-friendly software to convert X-ray images of resin-embedded samples into angles and cutting depths for the ultramicrotome. This is provided as an open-source Fiji plugin called Crosshair. This workflow is demonstrated by targeting regions of interest in a series of Platynereis dumerilii samples.

cell biology↗

bioRxiv2018

An alternative membrane topology permits lipid droplet localization of peroxisomal fatty acyl-CoA reductase 1

Fatty acyl-CoA reductase 1 (Far1) is an ubiquitously expressed peroxisomal membrane protein generating fatty alcohols required for the biosynthesis of ether lipids.\n\nLipid droplet localization of human Far1 was observed by fluorescence microscopy under conditions of increased triglyceride synthesis in tissue culture cells. This unexpected finding was supported further by correlative light electron microscopy and subcellular fractionation. Selective permeabilization and N-glycosylation tagging suggest that Far1 is able to assume two different membrane topologies, differing in the orientation of the short hydrophilic C-terminus towards the lumen or the cytosol, respectively. Two closely spaced hydrophobic domains are contained within the C-terminal region. When analyzed separately, the second domain was sufficient for the localization of a fluorescent reporter to lipid droplets. Targeting of Far1 to lipid droplets was not impaired in either pex19 or TRC40/ASNA1 CRISPR/Cas9 knockout cells.\n\nIn conclusion, our data suggest that Far1 is a novel member of the rather exclusive group of dual topology membrane proteins. At the same time, Far1 shows lipid metabolism-dependent differential subcellular localizations to peroxisomes and lipid droplets.

cell biology↗