Welcome to the Amira-Avizo Software Use Case Gallery

Ebola viruses (EBOVs) assemble into filamentous virions, whose shape and stability are determined by the matrix viral protein 40 (VP40). Virus entry into host cells occurs via membrane fusion in late endosomes; however, the mechanism of how the remarkably long virions undergo uncoating, including virion disassembly and nucleocapsid release into the cytosol, remains unknown. Here, we investigate the structural architecture of EBOVs entering host cells and discover that the VP40 matrix disassem... Read more

While fluorescence microscopy provides tools for highly specific labeling and sensitive detection, its resolution limit and lack of general contrast has hindered studies of cellular structure and protein localization. Recent advances in correlative light and electron microscopy (CLEM), including the fully integrated CLEM workflow instrument, the Thermo Scientific CorrSight with MAPS, have allowed for a more reliable, reproducible, and quicker approach to correlate three-dimensional time-lapse... Read more

Amira capacities for membranes and filaments segmentation in cryo-TEM images are featured on the front cover of Biochemical Journal, July 2020.

Budding yeast septins are essential for cell division and polarity. (…) [The authors] have dissected, here, for the first time, the behavior of the Shs1 protomer bound to membranes at nanometer resolution, in complex with the other septins. Using electron microscopy, [the authors] have shown that on membranes, Shs1 protomers self-assembl... Read more

The clinical use of bioactive molecules in bone regeneration has been known to have side effects, which result from uncontrolled and supraphysiological doses.

In this study, we demonstrated the synergistic effect of two bioactive molecules, bone morphogenic protein-2 (BMP-2) and alendronate (ALN), by releasing them in a sequential manner. Collagen-hydroxyapatite composite scaffolds functionalized using BMP-2 are loaded with biodegradable microspheres where ALN is encapsulated.
Th... Read more

Malignant cells are surrounded by a complex and supportive tumor microenvironment that consists of immune cells, extracellular matrix, vasculature, and fibroblasts. Cancer-associated fibroblasts (CAF) are the major cell type in the reactive stroma and are known to promote tumorigenesis and metastasis. Fibroblast activation protein alpha (FAP) is a transmembrane serine protease expressed by CAFs in the microenvironment of epithelial tumors.

Meta-analysis of FAP expression and clinical ... Read more

The matrix protein M1 of the Influenza A virus is considered to mediate viral assembly and budding at the plasma membrane (PM) of infected cells. In order for a new viral particle to form, the PM lipid bilayer has to bend into a vesicle towards the extracellular side. Studies in cellular models have proposed that different viral proteins might be responsible for inducing membrane curvature in this context (including M1), but a clear consensus has not been reached. In this study, we use a comb... Read more

Lamellar bodies (LBs) are surfactant rich organelles in alveolar type 2 cells. LBs disassemble into a lipid-protein network that reduces surface tension and facilitates gas exchange at the air-water interface in the alveolar cavity. Current knowledge of LB architecture is predominantly based on electron microscopy studies using disruptive sample preparation methods. We established a post-correlation on-lamella cryo-correlative light and electron microscopy approach for cryo-FIB milled lung ce... Read more

Cell-to-cell contact is essential for communication and development of multicellular organisms. A prerequisite is the passage through membranes. That way, molecular exchange and information flow is regulated via hormones, membrane proteins and pores.
In plants, the rigid cell walls prevent large membrane contact areas between protoplasts. Only plasmodesmata, minute channels between adjacent cells, form direct connections. Often, molecular data of the proteins involved are manifold but t... Read more

Centrioles are vital cellular structures that form centrosomes and cilia. The formation and function of cilia depends on a set of centriole’s distal appendages. In this study, we use correlative super resolution and electron microscopy to precisely determine where distal appendage proteins localize in relation to the centriole microtubules and appendage electron densities. Here we characterize a novel distal appendage protein ANKRD26 and detail, in high resolution, the initial steps of dist... Read more

In this work, we studied mitochondria-rER contacts in vivo by serial section electron tomography (SSET) and 3D reconstruction analysis of cryo-fixed mouse tissue samples. We characterized this inter-organelle association as mitochondria tightly wrapped by sheets of curved rER (wrappER). Further, we used multi-omics and genetic approaches to obtain evidence that the wrappER is a distinct intracellular compartment and demonstrate the importance of wrappER-mitochondria contacts for v... Read more

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the COVID19 pandemic, is a highly pathogenic β-coronavirus. As other coronaviruses, SARS-CoV-2 is enveloped, replicates in the cytoplasm and assembles at intracellular membranes. Here, we structurally characterize the viral replication compartment and report critical insights into the budding mechanism of the virus, and the structure of extracellular virions close to their native state by in situ cryo-electr... Read more

A novel archaeal virus, denoted Sulfolobus ellipsoid virus 1 (SEV1), was isolated from an acidic hot spring in Costa Rica. The morphologically unique virion of SEV1 contains a protein capsid with 16 regularly spaced striations and an 11-nm-thick envelope. The capsid exhibits an unusual architecture in which the viral DNA, probably in the form of a nucleoprotein filament, wraps around the longitudinal axis of the virion in... Read more

HIV-1 maturation occurs via multiple proteolytic cleavages of the Gag polyprotein, causing rearrangement of the virus particle required for infectivity. (…) How individual cleavages contribute to changes in protein structure and interactions, and how the mature, conical capsid forms, are poorly understood. Here, we employed cryoelectron tomography to determine morphology and high-resolution CA lattice structures for HIV1 derivatives in which Gag cleavage sites are mutated. These analyse... Read more

Mitochondria undergo spontaneous transient elevations in matrix pH associated with drops in mitochondrial membrane potential. These mitopHlashes require a functional respiratory chain and the profusion protein optic atrophy 1, but their mechanistic basis is unclear. To gain insight on the origin of these dynamic events, we resolved the ultrastructure of flashing mitochondria by correlative light and electron microscopy. HeLa cells expressing the matrix-targeted pH probe mitoSypHer were screen... Read more

Protein aggregation and dysfunction of the ubiquitin-proteasome system are hallmarks of many neurodegenerative diseases. Here, we address the elusive link between these phenomena by employing cryo-electron tomography to dissect the molecular architecture of protein aggregates within intact neurons at high resolution. We focus on the poly-Gly-Ala (poly-GA) aggregates resulting from aberrant translation of an expanded GGGGCC repeat in C9orf72, the most common genetic cause of amyotrophic latera... Read more

Correlative light and electron microscopy (CLEM) is a powerful approach to investigate the molecular ultrastructure of labeled cell compartments. However, quantitative CLEM studies are rare, mainly due to small sample sizes and the sensitivity of fluorescent proteins to strong fixatives and contrasting reagents for EM. Here, we show that fusion of…

The tissue inhibitor of metalloproteinases-1 (TIMP-1) exerts inhibitory activity against matrix metalloproteinases and cytokine-like effects. We previously showed that TIMP-1 reduces neurite outgrowth in mouse cortical neurons and that this cytokine-like effect depends on TIMP-1 endocytosis mediated by the low-density lipoprotein receptor-related protein-1 (LRP-1). To gain insight into the interaction between TIMP-1 and LRP-1, we considered conformational changes that occur when a ligand bind... Read more

Immunofluorescence tomography is a high-resolution 3-D reconstruction method based on methacrylate embedding and serial-sectioning, where 2-D images of immuno-stained serial-sections are computationally aligned into image stacks, and the 3-D volume rendered. Butyl-Methyl Methacrylate (BMMA) plastic was adopted as it preserves excellent tissue morphology and can be de-plasticized easily using an organic solvent, which enables immuno-staining of serial-sections without antibody penetration issu... Read more

Endothelial cells and pericytes are integral cellular components of the vasculature with distinct interactive functionalities. To study dynamic interactions between these two cells we created two transgenic animal lines. A truncated eNOS (endothelial nitric oxide synthase) construct was used as a GFP tag for endothelial cell evaluation and an inducible Cre-lox recombination, under control of the Pdgfrb (platelet derived growth factor receptor beta) promoter, was created for pericyte assessmen... Read more

Dense calcium caseinate dispersions can be transformed into hierarchically fibrous structures by shear deformation. This transformation can be attributed to the intrinsic properties of calcium caseinate. Depending on the dispersion preparation method, a certain amount of air gets entrapped in the sheared protein matrix. Although anisotropy is obtained in the absence of entrapped air, the fibrous appearance and mechanical anisotropy of the calcium caseinate materials are more pronounced with... Read more

Combined expansion and lattice light sheet microscopy enables high
speed, nanoscale molecular imaging of neural circuits over large volumes.

Optical and electron microscopy have made tremendous inroads in understanding the complexity of the brain, but the former offers insufficient resolution to reveal subcellular details and the latter lacks the throughput and molecular contrast to visualize specific molecular constituents over mm-scale or larger dimensions. We combined expansio... Read more