Content delivery to newly forming Weibel-Palade bodies is facilitated by multiple connections with the Golgi apparatus.

Weibel-Palade bodies (WPBs) comprise an on-demand storage organelle within vascular endothelial cells. It's major component, the hemostatic protein von Willebrand factor (VWF), is known to assemble into long helical tubules and is hypothesized to drive WPB biogenesis. However, electron micrographs of WPBs at the Golgi apparatus show that these forming WPBs contain very little tubular VWF compared with mature peripheral WPBs, which raises questions on the mechanisms that increase the VWF content and facilitate vesicle growth.

Correlative light microscopy and electron tomography to study Von Willebrand factor exocytosis from vascular endothelial cells.

Revealing the ultrastructure and function of fluorescently labeled cellular components by correlative light and electron microscopy (CLEM) facilitates the study of structure-function relationships in complex biological processes. Given the diversity of available fluorescent tags, light microscopy is ideal for monitoring dynamic cellular processes, while electron microscopy reveals the morphological context of structures at high resolution. Endothelial cells lining the blood vessel wall contain storage organelles called Weibel-Palade bodies (WPBs), which contain tubules of densely packed helical spirals of the blood coagulation protein Von Willebrand factor (VWF).

MAVIS: an integrated system for live microscopy and vitrification.

Cryo-electron microscopy of vitrified biological samples can provide three-dimensional reconstructions of macromolecules and organelles within bacteria and cells at nanometer scale resolution, even in native conditions. Localization of specific structures and imaging of cellular dynamics in cellular cryo-electron microscopy is limited by (i) the use of cryo-fixation to preserve cellular structures, (ii) the restricted availability of electron dense markers to label molecules inside cells and (iii) the inherent low contrast of cryo electron microscopy. These limitations can be mitigated to a large extend by correlative light and electron microscopy, where the sample is imaged by both light and electron microscopy.

Destruction of tissue, cells and organelles in type 1 diabetic rats presented at macromolecular resolution.

Finding alternatives for insulin therapy and making advances in etiology of type 1 diabetes benefits from a full structural and functional insight into Islets of Langerhans. Electron microscopy (EM) can visualize Islet morphology at the highest possible resolution, however, conventional EM only provides biased snapshots and lacks context. We developed and employed large scale EM and compiled a resource of complete cross sections of rat Islets during immuno-destruction to provide unbiased structural insight of thousands of cells at macromolecular resolution.

Glomerular endothelial surface layer acts as a barrier against albumin filtration.

Glomerular endothelium is highly fenestrated, and its contribution to glomerular barrier function is the subject of debate. In recent years, a polysaccharide-rich endothelial surface layer (ESL) has been postulated to act as a filtration barrier for large molecules, such as albumin. To test this hypothesis, we disturbed the ESL in C57Bl/6 mice using long-term hyaluronidase infusion for 4 weeks and monitored albumin passage using immunolabeling and correlative light-electron microscopy that allows for complete and integral assessment of glomerular albumin passage.

Virtual nanoscopy: generation of ultra-large high resolution electron microscopy maps.

A key obstacle in uncovering the orchestration between molecular and cellular events is the vastly different length scales on which they occur. We describe here a methodology for ultrastructurally mapping regions of cells and tissue as large as 1 mm(2) at nanometer resolution. Our approach employs standard transmission electron microscopy, rapid automated data collection, and stitching to create large virtual slides.

Cryo-electron tomography of mouse hepatitis virus: Insights into the structure of the coronavirion.

Coronaviruses are enveloped viruses containing the largest reported RNA genomes. As a result of their pleomorphic nature, our structural insight into the coronavirion is still rudimentary, and it is based mainly on 2D electron microscopy. Here we report the 3D virion structure of coronaviruses obtained by cryo-electron tomography.