Biology subjects

Pfaff, F.

Publications and source records attributed to Pfaff, F..

3 recordsLinked to original sources

bioRxiv2022

Mystery of fatal "Staggering disease" unravelled: Novel rustrela virus causes severe encephalomyelitis in domestic cats

Staggering disease is a neurological disorder considered a threat to European domestic cats (Felis catus) for almost five decades. However, its aetiology has remained obscure. Rustrela virus (RusV), a relative of rubella virus, has recently been shown to be associated with encephalitis in a broad range of mammalian hosts. Here, we report the detection of RusV RNA and antigen by metagenomic sequencing, RT-qPCR, in-situ hybridization and immunohistochemistry in brain tissues of 28 out of 29 cats with non-suppurative meningoencephalomyelitis and staggering disease-like neurological disorder from Sweden, Austria, and Germany, but not in non-affected control cats. Screening of possible reservoir hosts in Sweden revealed RusV infection in wood mice (Apodemus sylvaticus). Our work strongly indicates RusV as the long-sought cause of feline staggering disease. Given its broad host spectrum and considerable geographic range, RusV may be the aetiological agent of neuropathologies in further mammals, possibly even including humans.

microbiology↗

bioRxiv2021

Revisiting rustrela virus - new cases of encephalitis and a solution to the capsid enigma

Rustrela virus (RusV, species Rubivirus strelense) is a recently discovered relative of rubella virus (RuV) that has been detected in cases of encephalitis across a wide spectrum of mammals, including placental and marsupial animals. Here we diagnosed two additional cases of fatal RusV-associated meningoencephalitis in a South American coati (Nasua nasua) and a Eurasian otter (Lutra lutra) that were detected in a zoological garden with history of prior RusV infections. Both animals showed abnormal movement or unusual behaviour and their brains tested positive for RusV using specific RT-qPCR and RNA in situ hybridization. As previous sequencing of RusV proved to be very challenging, we employed a sophisticated target-specific capture enrichment with specifically designed RNA baits to generate complete RusV genome sequences from both detected encephalitic animals and apparently healthy wild yellow-necked field mice (Apodemus flavicollis). Furthermore, the technique was used to revise three previously published RusV genomes from two encephalitic animals and a wild yellow-necked field mouse. Virus-to-host sequence ratio and thereby sequence coverage improved markedly using the enrichment method as compared to standard procedures. When comparing the newly generated RusV sequences to the previously published RusV genomes, we identified a previously undetected stretch of 309 nucleotides predicted to represent the intergenic region and the sequence encoding the N-terminus of the capsid protein. This indicated that the original RusV sequence was likely incomplete due to misassembly of the genome at a region with an exceptionally high G+C content of >80 mol%, which could not be resolved even by enormous sequencing efforts with standard methods. The updated capsid protein amino acid sequence now resembles those of RuV and ruhugu virus in size and harbours a predicted RNA binding domain that was not encoded in the original RusV genome version. The new sequence data indicate that RusV has the largest overall genome (9,631 nucleotides), intergenic region (290 nucleotides) and capsid protein-encoding sequence (331 codons) within the genus Rubivirus.

microbiology↗

bioRxiv2021

Adherent and suspension baby hamster kidney cells have a different cytoskeleton and surface receptor repertoire

Animal cell culture, with single cells growing in suspension, ideally in a chemically defined environment, is a mainstay of biopharmaceutical production. The synthetic environment lacks exogenous growth factors and usually requires a time-consuming adaptation process to select cell clones that proliferate in suspension to high cell numbers. The molecular mechanisms that facilitate the adaptation and that take place inside the cell are largely unknown. Especially for cell lines that are used for virus antigen production such as baby hamster kidney (BHK) cells, the restriction of virus growth through the evolution of undesired cell characteristics is highly unwanted. The comparison between adherently growing BHK cells and suspension cells with different susceptibility to foot-and-mouth disease virus revealed differences in the expression of cellular receptors such as integrins and heparan sulfates, and in the organization of the actin cytoskeleton. Transcriptome analyses and growth kinetics demonstrated the diversity of BHK cell clones and confirmed the importance of well-characterized parental cell clones and mindful screening to make sure that essential cellular features do not get lost during adaptation.

cell biology↗