Sialidase and hyaluronidase production by the wild-type, mutant and complemented strains.
Quantitative assays were carried out to determine the relative amount of extracellular enzyme production by the wild-type, mutant and complemented strains at time of inoculation and 4 h and 8 h post-inoculation (corresponding to exponential and stationary growth phases, respectively). Sialidase assays were performed using culture supernatants from cultures grown in Todd-Hewitt broth (A). Hyaluronidase activity was determined using the cell lysates from cultures grown in TPYG (B). All results are given as the average of three biological replicates (± SEM) for sialidase assays and six biological replicates for hyaluronidase assays; the asterisk (*) denotes a statistically significant difference (p≤0.05) as determined by the student’s t-test.