Cellular & Molecular Imaging

1) Light-sheet movies of the surface of chick embryos treated with different chemicals at cellular resolution. Ideal to study individual cell behaviours and tissue flows in epithelial tissues. 2) Confocal images of SNAI2 and pMLC2 of chick embryos treated with different chemicals.

The ability of a single protein to trigger different functions is an assumed key feature of cell signaling, yet there are very few examples demonstrating it. Here, using an optogenetic tool to control membrane localization of RhoA nucleotide exchange factors (GEFs), we present a case where the same protein can trigger both protrusion and retraction when recruited to the plasma membrane, polarizing the cell in two opposite directions. We show that the basal concentration of the GEF prior to activation predicts the resulting phenotype. A low concentration leads to retraction, whereas a high concentration triggers protrusion. This unexpected protruding behavior arises from the simultaneous activation of Cdc42 by the GEF and sequestration of active RhoA by the GEF PH domain at high concentrations. We propose a minimal model that recapitulates the phenotypic switch, and we use its predictions to control the two phenotypes within selected cells by adjusting the frequency of light pulses. Our work exemplifies a unique case of control of antagonist phenotypes by a single protein that switches its function based on its concentration or dynamics of activity. It raises numerous open questions about the link between signaling protein and function, particularly in contexts where proteins are highly overexpressed, as often observed in cancer.

This dataset contains over 20000 images of Dipteran wings collected, mostly of mosquitos. Each image is accompanied by extensive metadata, accessible in the 00_metadata.* files. The dataset aims to facilitate research in wing geometric morphometry and support the development of machine learning models for advancing vector surveillance and research. It is a retrospective collection, harmonizing contributions from research projects conducted between 2008 and 2026. The detailed metadata on each sample and image is available in the 00_metadata.*. This table below will provide an overview of the scope and range of the collected metadata. Due to the retrospective nature of the dataset, images may vary significantly in aspects such as lighting, background, and capture conditions across different projects. Although extensive efforts were made to ensure comprehensive metadata, some entries remain incomplete. Missing metadata entries are marked as MISSING VALUE," while fields intentionally left blank are indicated with "-". For the full description of the dataset we refer to the associated publication: https://www.nature.com/articles/s41597-025-05043-3#Sec5

Oblique plane microscopy (OPM) is a form of light-sheet fluorescence microscopy (LSFM) employing a single microscope objective at the sample for both fluorescence excitation and detection. Dual-view OPM (dOPM) is an optically folded form of OPM. We present an improved dOPM system employing a 60×/1.2NA water immersion primary objective and measure the spatial resolution and fluorescence collection efficiency for illumination angles of 35° and 45° with respect to the coverslip. Illumination at 35° provides slightly better lateral resolution and collection efficiency. Collection efficiency measurements are compared to a full vectorial raytracing simulation of the system. Using a light-sheet angle of 35°, the median bead FWHM for 100 nm diameter fluorescent beads in x, y and z and the optical sectioning strength were measured over a volume of 100×100×100 μm³, to be 0.29, 0.31, 0.83 and 2.45-3.00 μm respectively when the two dOPM views are fused. We demonstrate less photobleaching in time-lapse dOPM of live mEmerald-expressing organoids compared to widefield epi-fluorescence z-stack imaging under the condition of equal detected fluorescence signal from a point object in focus. We demonstrate dOPM for multi-field-of-view 3D imaging of biological samples in 96-well plates and apply it to imaging cells in collagen gel and quantifying the FUCCI cell-cycle reporter to provide drug dose-response curves in spheroids. We also use it to perform time-lapse multi-field-of-view imaging and demonstrate the detection of organoid lumen closure and reopening, organoid migration within a collagen gel and observing dynamic events in arrays of ex vivo tissue slices.

The Darwin Tree of Life project has the goal to sequence the genomes of 70,000 species of eukaryotic organisms in Britain and Ireland. This is a collection of photographs of the samples included in the study, provided by the National History Museum (NHM).

Mosquito-Alert http://www.mosquitoalert.com/ is a cooperative citizen science observatory coordinated by different public research institutions. Its main objective is to monitor the spread of invasive species of mosquitoes, particularly the tiger mosquito and the yellow fever mosquito, vectors of global diseases like Zika, Dengue and Chikungunya. The Mosquito-Alert app allows citizens to report a possible finding of the targeted species or their breeding places on the public space by sending images. The app collects the GPS position and other related information along with the image. Afterwards, a team of entomology experts validates the images. The validation is sent back to the participant and published in a public map of observations.

This repository contains high-resolution confocal microscopy datasets of mosquito larval midgut tissues exposed to Bacillus thuringiensis Cry toxins and fluorescent markers for cellular organelles. The data were collected using an Olympus FV1000 confocal laser scanning microscope with a 60X oil immersion objective and a pixel size of 59 nm. The datasets include images of Cry toxins labeled with Alexa Fluor dyes and markers such as SiR-Actin, SiR-Lysosomes, MitoTracker, FM4-64, ER-Tracker, and DAPI. Each dataset represents independent replicates from midgut tissue dissections of at least five larvae per experimental condition.

X-chromosome inactivation

Eukaryotic chromosome segregation requires attachment of chromosomes to microtubules through the kinetochore so that chromosomes can align and move in mitosis. Kinetochores assemble on the centromere which is epigenetically defined by the histone H3 variant CENtromere Protein A (CENP-A). During DNA replication CENP-A is equally divided between replicated chromatids and new CENP-A nucleosomes are re-assembled during the subsequent G1 phase. How cells regulate the cell cycle timing of CENP-A assembly is a central question in the epigenetic maintenance of centromeres. CENP-A nucleosome assembly requires the Mis18 complex (Mis18α, Mis18β, and M18BP1) which is regulated in its localization to centromeres between metaphase and G1. Here, we define a new regulatory mechanism that works through phosphorylation of Xenopus laevis M18BP1 between metaphase and interphase. This switch disrupts binding of M18BP1 to CENP-A nucleosomes in metaphase, and when relieved enables M18BP1 binding to CENP-A nucleosomes in interphase. We show that this phosphorylation dependent mechanism regulates CENP-A nucleosome assembly. We propose that the phospho-regulated binding of M18BP1 to CENP-A nucleosomes restricts new CENP-A assembly to interphase.

This repository contains Transmission Electron Microscopy (TEM) datasets of mosquito larval midgut tissues, focusing on the brush border membrane (BBM) and midgut lumen regions in control larvae without toxin treatment. Samples were prepared using standard protocols for fixation, dehydration, and embedding, with larvae reared under controlled conditions prior to dissection. Ultra-thin sections (60 nm) were obtained using an ultramicrotome and stained with uranyl acetate and lead citrate to enhance contrast. Imaging was performed using a ZEISS Libra 120 Plus electron microscope operated at 80 kV, capturing ultrastructural details at magnifications ranging from 1500× to 5000×, with micrographs acquired via a GATAN UltraScan 1000 CCD camera.