Characterization of Pulmonary Pathology in the Golden Syrian Hamster Model of COVID-19 Using Micro-Computed Tomography.

The Golden Syrian hamster is a well-characterized rodent model for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-associated pneumonia. We sought to characterize the pulmonary disease course during SARS-CoV-2 infection (strain USA-WA1/2020) in the hamster model using micro-computed tomography (micro-CT) and compare radiologic observations with histopathologic findings. We observed a range of radiologic abnormalities, including ground glass opacities (GGOs), consolidations, air bronchograms, and pneumomediastinum.

Directed Evolution of a Bacterial Leucyl tRNA in Mammalian Cells for Enhanced Noncanonical Amino Acid Mutagenesis.

The leucyl-tRNA synthetase (EcLeuRS)/tRNA pair has been engineered to genetically encode a structurally diverse group of enabling noncanonical amino acids (ncAAs) in eukaryotes, including those with bioconjugation handles, environment-sensitive fluorophores, photocaged amino acids, and native post-translational modifications. However, the scope of this toolbox in mammalian cells is limited by the poor activity of tRNA. Here, we overcome this limitation by evolving tRNA directly in mammalian cells by using a virus-assisted selection scheme.

avoids toxin-producing using a seven transmembrane domain chemosensory receptor.

Predators and prey co-evolve, each maximizing their own fitness, but the effects of predator-prey interactions on cellular and molecular machinery are poorly understood. Here, we study this process using the predator and the bacterial prey which have evolved a powerful defense: the production of nematicides. We demonstrate that upon exposure to at their head or tail, nematodes display an escape response that is mediated by bacterially produced cues.