Electron microscopy images and morphometric data of SARS-CoV-2 variants in ultrathin plastic sections.

Conventional thin section electron microscopy of viral pathogens, such as the pandemic SARS-CoV-2, can provide structural information on the virus particle phenotype and its evolution. We recorded about 900 transmission electron microscopy images of different SARS-CoV-2 variants, including Alpha (B.1.

-containing spheres are a novel and predominant form of egress by the pathogen .

The egress of intracellular bacteria from host cells and cellular tissues is a critical process during the infection cycle. This process is essential for bacteria to spread inside the host and can influence the outcome of an infection. For the obligate intracellular Gram-negative zoonotic bacterium little is known about the mechanisms resulting in bacterial egress from the infected epithelium.

LRBA, a BEACH protein mutated in human immune deficiency, is widely expressed in epithelia, exocrine and endocrine glands, and neurons.

Mutations in LRBA, a BEACH domain protein, cause severe immune deficiency in humans. LRBA is expressed in many tissues and organs according to biochemical analysis, but little is known about its cellular and subcellular localization, and its deficiency phenotype outside the immune system. By LacZ histochemistry of Lrba gene-trap mice, we performed a comprehensive survey of LRBA expression in numerous tissues, detecting it in many if not all epithelia, in exocrine and endocrine cells, and in subpopulations of neurons.

General, Modular Access toward Immobilized Chiral Phosphoric Acid Catalysts and Their Application in Flow Chemistry.

Chiral phosphoric acids (CPAs) are among the most frequently used organocatalysts, with an ever-increasing number of applications. However, these catalysts are only obtained in a multistep synthesis and are poorly recyclable, which significantly deteriorates their environmental and economic performance. We herein report a conceptually different, general strategy for the direct immobilization of CPAs on a broad scope of solid supports including silica, polystyrene, and aluminum oxide.

A recent gibbon ape leukemia virus germline integration in a rodent from New Guinea.

Germline colonization by retroviruses results in the formation of endogenous retroviruses (ERVs). Most colonization's occurred millions of years ago. However, in the Australo-Papuan region (Australia and New Guinea), several recent germline colonization events have been discovered The Wallace Line separates much of Southeast Asia from the Australo-Papuan region restricting faunal and pathogen dispersion.

Selective replication and vertical transmission of Ebola virus in experimentally infected Angolan free-tailed bats.

The natural reservoir of Ebola virus (EBOV), agent of a zoonosis burdening several African countries, remains unidentified, albeit evidence points towards bats. In contrast, the ecology of the related Marburg virus is much better understood; with experimental infections of bats being instrumental for understanding reservoir-pathogen interactions. Experiments have focused on elucidating reservoir competence, infection kinetics and specifically horizontal transmission, although, vertical transmission plays a key role in many viral enzootic cycles.

Analysis of Sporulation in Biovar Which Contains an Insertion in the Gene for the Sporulation Factor σ.

biovar () is an untypical pathogen causing a fatal anthrax-like disease in a variety of wildlife species in African rainforest areas. In contrast to and most species of the group, all strains of the cluster contain a 22 kb insertion in the gene which encodes the essential late sporulation sigma factor σ. This insertion is excised during sporulation in a site-specific recombination process resulting in an intact gene and a circular molecule.

Dynamic ventral disc contraction is necessary for attachment and host pathology.

is a common parasitic protist that infects the small intestine and causes giardiasis, resulting in diarrhea, vomiting, weight loss, and malabsorption. Giardiasis leads to cellular damage, including loss of microvilli, disruption of tight junctions, impaired barrier function, enzyme inhibition, malabsorption, and apoptosis. In the host, motile trophozoites attach to the duodenal microvilli using a unique microtubule organelle called the ventral disc.

The domed architecture of Giardias ventral disc is necessary for attachment and host pathogenesis.

After ingestion of dormant cysts, the widespread protozoan parasite Giardia lamblia colonizes the host gastrointestinal tract via direct and reversible attachment using a novel microtubule organelle, the ventral disc. Extracellular attachment to the host allows the parasite to resist peristaltic flow, facilitates colonization and is proposed to cause damage to the microvilli of host enterocytes as well as disrupt host barrier integrity. The 9 um in diameter ventral disc is defined by a highly complex architecture of unique protein complexes scaffolded onto a spiral microtubule (MT) array of one hundred parallel, uniformly spaced MT polymers that bend approximately one and a quarter turns to form a domed structure.

A Family of Spore Lipoproteins Stabilizes the Germination Apparatus by Altering Inner Spore Membrane Fluidity in Spores.

Dormant bacterial spores undergo the process of germination to return to a vegetative state. In most species, germination involves the sensing of nutrient germinants, the release of various cations and a calcium-dipicolinic acid (DPA) complex, spore cortex degradation, and full rehydration of the spore core. These steps are mediated by membrane-associated proteins, and all these proteins have exposure on the outer surface of the membrane, a hydrated environment where they are potentially subject to damage during dormancy.

Facile modification of phosphole-based aggregation-induced emission luminogens with sulfonyl isocyanates.

Phosphole oxides undergo a highly chemoselective reaction with sulfonyl isocyanates forming sulfonylimino phospholes in high yields. This facile modification proved to be a powerful tool for obtaining new phosphole-based aggregation-induced emission (AIE) luminogens with high fluorescence quantum yields in the solid state. Changing the chemical environment of the phosphorus atom of the phosphole framework results in a significant shift of the fluorescence maximum to longer wavelengths.

Distinct tissue niches direct lung immunopathology via CCL18 and CCL21 in severe COVID-19.

Prolonged lung pathology has been associated with COVID-19, yet the cellular and molecular mechanisms behind this chronic inflammatory disease are poorly understood. In this study, we combine advanced imaging and spatial transcriptomics to shed light on the local immune response in severe COVID-19. We show that activated adventitial niches are crucial microenvironments contributing to the orchestration of prolonged lung immunopathology.

Visualization of SARS-CoV-2 particles in naso/oropharyngeal swabs by thin section electron microscopy.

Background: SARS-CoV-2 replicates efficiently in the upper airways of humans and produces high loads of virus RNA and, at least in the initial phase after infection, many infectious virus particles. Studying virus ultrastructure, such as particle integrity or presence of spike proteins, and effects on their host cells in patient samples is important to understand the pathogenicity of SARS-CoV-2.

Methods: Suspensions from swab samples with a high load of virus RNA (Ct < 20) were sedimented by desktop ultracentrifugation and prepared for thin section electron microscopy using a novel method which is described in detail.

SARS-CoV-2 Omicron variant is attenuated for replication in a polarized human lung epithelial cell model.

SARS-CoV-2 and its emerging variants of concern remain a major threat for global health. Here we introduce an infection model based upon polarized human Alveolar Epithelial Lentivirus immortalized (hAELVi) cells grown at the air-liquid interface to estimate replication and epidemic potential of respiratory viruses in the human lower respiratory tract. hAELVI cultures are highly permissive for different human coronaviruses and seasonal influenza A virus and upregulate various mediators following virus infection.

Colony growth and biofilm formation of under simulated microgravity.

The biotechnology- and medicine-relevant fungus is a common colonizer of indoor habitats such as the International Space Station (ISS). Being able to colonize and biodegrade a wide range of surfaces, can ultimately impact human health and habitat safety. Surface contamination relies on two key-features of the fungal colony: the fungal spores, and the vegetative mycelium, also known as biofilm.

Assessing and improving the validity of COVID-19 autopsy studies - A multicentre approach to establish essential standards for immunohistochemical and ultrastructural analyses.

Background: Autopsy studies have provided valuable insights into the pathophysiology of COVID-19. Controversies remain about whether the clinical presentation is due to direct organ damage by SARS-CoV-2 or secondary effects, such as overshooting immune response. SARS-CoV-2 detection in tissues by RT-qPCR and immunohistochemistry (IHC) or electron microscopy (EM) can help answer these questions, but a comprehensive evaluation of these applications is missing.

The Sensilla-Specific Expression and Subcellular Localization of SNMP1 and SNMP2 Reveal Novel Insights into Their Roles in the Antenna of the Desert Locust .

Insect olfactory sensilla house olfactory sensory neurons (OSNs) and supports cells (SCs). The olfactory sensory processes require, besides the odorant receptors (ORs), insect-specific members of the CD36 family, named sensory neuron membrane proteins (SNMPs). While SNMP1 is considered to act as a coreceptor in the OR-mediated detection of pheromones, SNMP2 was found to be expressed in SCs; however, its function is unknown.

Identification of coronavirus particles by electron microscopy requires demonstration of specific ultrastructural features.

https://bit.ly/3IFYDjc

A Conserved Cysteine Residue in Coxsackievirus B3 Protein 3A with Implication for Elevated Virulence.

Enteroviruses (EV) are implicated in an extensive range of clinical manifestations, such as pancreatic failure, cardiovascular disease, hepatitis, and meningoencephalitis. We recently reported on the biochemical properties of the highly conserved cysteine residue at position 38 (C38) of enteroviral protein 3A and demonstrated a C38-mediated homodimerization of the Coxsackievirus B3 protein 3A (CVB3-3A) that resulted in its profound stabilization. Here, we show that residue C38 of protein 3A supports the replication of CVB3, a clinically relevant member of the enterovirus genus.

Ultrastructural examination of lung "cryobiopsies" from a series of fatal COVID-19 cases hardly revealed infected cells.

Ultrastructural analysis of autopsy samples from COVID-19 patients usually suffers from significant structural impairment possibly caused by the rather long latency between death of the patient and an appropriate sample fixation. To improve structural preservation of the tissue, we obtained samples from ventilated patients using a trans-bronchial "cryobiopsy" within 30 min after their death and fixed them immediately for electron microscopy. Samples of six COVID-19 patients with a documented histopathology were systematically investigated by thin section electron microscopy.