Photodynamic Inactivation of SARS-CoV-2 Infectivity and Antiviral Treatment Effects In Vitro.

Despite available vaccines, antibodies and antiviral agents, the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic still continues to cause severe disease and death. Current treatment options are limited, and emerging new mutations are a challenge. Thus, novel treatments and measures for prevention of viral infections are urgently required.

Analysis and optimization of a Caco-2 cell culture model for infection with human norovirus.

Human noroviruses (hNoVs) are an important cause of acute gastroenteritis worldwide. However, the lack of a reproducible in vitro cell culture system has impaired research and the development of preventive measures, therapeutic drugs, and vaccines. The aim of this study was to analyze and optimize a suitable cell line for in vitro cultivation of hNoV.

No SARS-CoV-2 detected in air samples (pollen and particulate matter) in Leipzig during the first spread.

The SARS-CoV-2 pandemic co-occurred with pollen season in Europe 2020 and recent studies suggest a potential link between both. Air samples collected at our measuring station in Leipzig and purified pollen were analyzed for SARS-CoV-2 typical signals or for virus-induced cytopathic effects, to test if the virus could bind to bioaerosols and if so, whether these complexes are infectious. The results show that neither our air samples nor purified pollen were infectious or could act as carrier for virus particles.

The Host Factor AUF1 p45 Supports Flavivirus Propagation by Triggering the RNA Switch Required for Viral Genome Cyclization.

In previous studies, we showed that the cellular RNA-binding protein AUF1 supports the replication process of the flavivirus West Nile virus. Here we demonstrate that the protein also enables effective proliferation of dengue virus and Zika virus, indicating that AUF1 is a general flavivirus host factor. Further studies demonstrated that the AUF1 isoform p45 significantly stimulates the initiation of viral RNA replication and that the protein's RNA chaperone activity enhances the interactions of the viral 5'UAR and 3'UAR genome cyclization sequences.

Arginine methylation enhances the RNA chaperone activity of the West Nile virus host factor AUF1 p45.

A prerequisite for the intracellular replication process of the Flavivirus West Nile virus (WNV) is the cyclization of the viral RNA genome, which enables the viral replicase to initiate RNA synthesis. Our earlier studies indicated that the p45 isoform of the cellular AU-rich element binding protein 1 (AUF1) has an RNA chaperone activity, which supports RNA cyclization and viral RNA synthesis by destabilizing a stem structure at the WNV RNA's 3'-end. Here we show that in mammalian cells, AUF1 p45 is consistently modified by arginine methylation of its C terminus.