Fig. 1: IAV shape distribution is dynamic.
From: Influenza A virus rapidly adapts particle shape to environmental pressures
a, A schematic illustrating the VSSC of virions of varying sizes. Large virions such as filaments scatter violet light more than smaller ones such as spheres. b, Top: representative electron micrographs of IAV virion samples sphere-enriched or filament-enriched by sucrose gradient ultracentrifugation; five independent samples containing a range of shape profiles were analysed. Bottom: corresponding VSSC histograms of the above samples. Violet side scatter of virions is mostly resolved from noise inherent to small-particle flow cytometry. c, Representative flow virometry data for unpurified infection supernatants. To distinguish highly dilute virus signal from noise, virions are bound with a fluorescently labelled HA antibody (Sb H36-26) to enable separation in two detection channels. Displayed are scatterplots of VSSC versus fluorescence with gates enclosing virions (dashed area, top), along with corresponding VSSC histograms of the gated population (bottom). Percentage of filamentous virions for each sample are indicated. d, Time courses of virion yields (left) and shape (right), determined by flow virometry of supernatants from MDCK cells infected with PR8 at MOI 0.006 (Low MOI, open symbols) or MOI 6 (High MOI, filled symbols). No-spread infections (dashed lines) were achieved by omitting trypsin. Mean and s.e.m. are plotted. The blue bars highlight the samples with raw data shown in c. Grey shading indicates yields too low to reliably measure shape. e–g, Same as d, but for XUdorn infections in MDCK cells (e), PR8 infections in Calu3 cells (f) and XUdorn infections in Calu3 cells (g). For Calu3 infections, no-spread infections were achieved by adding ammonium chloride at 4 h post infection (h.p.i.) d–g, Data plotted are from three biological replicates.
