Welcome to the Amira-Avizo Software Use Case Gallery

Retroviruses evolved from long terminal repeat (LTR) retrotransposons by acquisition of envelope functions, and subsequently reinvaded host genomes. Together, endogenous retroviruses and LTR retrotransposons represent major components of animal, plant, and fungal genomes. Sequences from these elements have been exapted to perform essential host functions, including placental development, synaptic communication, and transcriptional regulation. They encode a Gag polypeptide, the capsid domains ... Read more

Corpora amylacea are cell-derived structures that appear physiologically in the aged human brain. While their histological identification is straightforward, their ultrastructural composition and microenvironment at the nanoscale have remained unclear so far, as has their relevance to aging and certain disease states that involve the sequestration of toxic cellular metabolites. Here, we apply correlative serial block-face scanning electron microscopy and transmission electron tomograp... 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

Microbial parasites may behave collectively to manipulate their host’s behavior. We examine adaptations of a microbial parasite in its natural environment: the body of its coevolved and manipulated host.

Electron microscopy and 3D reconstructions of host and parasite tissues reveal that this fungus invades muscle fibers throughout the ant’s body but leaves the brain intact, and that the fungal cells connect to form extensive networks.

The importance of context in regulation of gene expression is now an accepted principle; yet the mechanism by which the microenvironment communicates with the nucleus and chromatin in healthy tissues is poorly understood. A functional role for nuclear and cytoskeletal architecture is suggested by the phenotypic differences observed between epithelial and mesenchymal cells…

Intracellular pathogens include all viruses, many bacteria and parasites capable of invading and surviving within host cells. Key to survival is the subversion of host cell pathways by the pathogen for the purpose of propagation and evading the immune system. The intracellular bacterium Shigella flexneri, the causative agent of bacillary dysentery, invades host cells in a vacuole that is subsequently ruptured to allow growth of the pathogen within the host cytoplasm…

Bacteria of the phylum Planctomycetes have been previously reported to possess several features that are typical of eukaryotes, such as cytosolic compartmentalization and endocytosis-like macromolecule uptake. However, recent evidence points towards a Gram-negative cell plan for Planctomycetes, although in-depth experimental analysis has been hampered by insufficient genetic tools…

Positive-strand RNA viruses, which can be devastating pathogens in humans, animals and plants, replicate their genomes on intracellular membranes. Here, we describe the three-dimensional ultrastructural organization of a tombusvirus replicase in yeast, a valuable model for exploring virus–host interactions…

Intravital microscopy provides dynamic understanding of multiple cell biological processes, but its limited resolution has so far precluded structural analysis. Because it is difficult to capture rare and transient events, only a few attempts have been made to observe specific developmental and pathological processes in animal models using electron microscopy. The multimodal correlative approach that we propose here combines intravital microscopy, microscopic X-ray computed tomography and thr... 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

The fruit fly, Drosophila melanogaster, is an important experimental model to address central questions in neuroscience at an organismic level. However, imaging of neural circuits in intact fruit flies is limited due to structural properties of the cuticle. Here we present a novel approach combining tissue clearing, ultramicroscopy, and data analysis that enables the visualisation of neuronal networks with single-cell resolution from the larval stage up to the adult Drosophila. (…) This... Read more

With the advent of neurogenetic methods, the neural basis of behavior is presently being analyzed in more and more detail. This is particularly true for visually driven behavior of Drosophila melanogaster where cell-specific driver lines exist that, depending on the combination with appropriate effector genes, allow for targeted recording, silencing and optogenetic stimulation of individual cell-types. Together with detailed connectomic data of large parts of the fly optic lobe, this has rece... Read more

COPI-coated vesicles mediate trafficking within the Golgi apparatus and from the Golgi to the endoplasmic reticulum. Here, we applied cryo-focused ion beam milling, cryo-electron tomography and subtomogram averaging to determine the native structure of the COPI coat within vitrified Chlamydomonas reinhardtii cells. The native algal structure resembles the in vitro mammalian structure, but additionally reveals cargo bound beneath beta’–COP. We find that all coat components disassemble... 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

The major mammalian bloodstream form of the African sleeping sickness parasite Trypanosoma bruceimultiplies rapidly, and it is important to understand how these cells divide. Organelle inheritance involves complex spatiotemporal re-arrangements to ensure correct distribution to daughter cells…

Podocytes present a unique 3D architecture specialized for glomerular filtration. However, several 3D morphological aspects on podocyte development remain partially understood because they are difficult to reveal using conventional scanning electron microscopy (SEM). Here, we adopted serial block-face SEM imaging…

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…

Serial block-face electron microscopy (SBEM) provides nanoscale 3D ultrastructure of embedded and stained cells and tissues in volumes of up to 10⁷ µm³. In SBEM, electrons with 1–3 keV energies are incident on a specimen block, from which backscattered electron (BSE) images are collected with x, y resolution of 5–10 nm in the block-face plane, and successive layers are removed by an in situ ultramicrotome. Sp... Read more

The orchestration of intercellular communication is essential for multicellular organisms. One mechanism by which cells communicate is through long, actin-rich membranous protrusions called tunneling nanotubes (TNTs), which allow the intercellular transport of various cargoes, between the cytoplasm of distant cells in vitro and in vivo. Here, we use correlative FIB-SEM, light- and cryo-electron microscopy approaches to elucidate the structural organization of neuronal TNTs. Our data indicate ... Read more

During the acts of biting and chewing, the muscles of the jaw (consisting of the masseter, temporalis, and medial pterygoid in the elevator group, and lateral pterygoid as the main depressor) generate forces that dictate jaw kinematics . The movement of jaws hinges about the temporomandibular joint and are brought together by the muscles attached to respective bones through bone-tendon interfaces known as entheses . Thus, chewing forces affect aspects of craniofacial structure as well as bo... Read more