rPR8 M1 R101G and rPR8 M1 N87S viruses have higher neuraminidase activity than rPR8wt virus.

<p>A) Neuraminidase enzyme kinetics. Virus input was standardized to 5×10⁵ PFU and concentrations of MUNANA substrate ranging from 1.17 µM to 150 µM were used. Fluorescence generated at each time point (every minute over the course of 1 hour) was detected using a Biotek Synergy H1 plate reader. The resulting fluorescence curves were then fitted to the Michaelis-Menton equation. B) That equivalent amounts of each virus were used in the MUNANA assay was confirmed by RT-qPCR for the viral NP segment. The arithmetic mean (n = 3) and standard deviation of 2^(−Cq) values were calculated and then converted back to a C_q scale by taking the log₂. Two biological replicates of each virus are included in white and grey bars; each biological replicate comprised three technical replicates.