Ultracentrifugation deforms unfixed influenza A virions

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Negatively stained influenza virions sometimes show irregular morphology and are often referred to as pleomorphic. However, this irregular morphology has not been visualized when ultrathin-section transmission and scanning electron microscopies are used. This study focused on the effects of ultracentrifugation on influenza A virion morphology, as negative staining often involves ultracentrifugation to concentrate or purify virions. The morphologies of unfixed, glutaraldehyde-fixed and osmium tetroxide-fixed virions were quantitatively compared before and after ultracentrifugation, and it was found that, without chemical fixation, approximately 30 % of virions were altered from oval to irregular shapes following ultracentrifugation. By contrast, most glutaraldehyde-fixed virions remained uniformly elliptical, even after ultracentrifugation. When a virus with an 11 aa deletion at the C terminus of its M2 cytoplasmic tail was ultracentrifuged, its morphology was appreciably deformed compared with that of the wild-type virus. These results demonstrate that the native morphology of influenza A virions is regular but is disrupted by ultracentrifugation, and that the cytoplasmic tail of M2 is important for virion integrity.

This publication has 29 references indexed in Scilit: