Fig 4.

Effect of aerosol pH on IAV structural integrity. IAV was adjusted to pH 4, then neutralized back to pH 7 after 30 s, control samples were mock-adjusted to pH 7 for the same time period, or were suspended in PBS only. (A) Neutralized and control samples were fixed in PFA and then stained with 2% uranyl acetate and imaged using the Tecnai Spirit TEM (imaged at 30,000× and 120,000× magnification). Images are representative of duplicate samples. (B) Alternatively, neutralized virus samples were incubated in the presence of RNase or PBS (no RNase control) prior to RNA extraction and genome quantification by RT-qPCR. Data were presented as mean genome copies/mL ± SD for triplicate samples. Data were analyzed by two-way ANOVA (**P < 0.01, ***P < 0.001, ns, not significant).