FIG 3.

The ΔgltT ΔgltM invasion defect was observed only under physiological glutamate conditions and only at higher MOIs. Shown are adherence (A), internalization (B), and the internalization/adhesion ratio (percent internalized) (C) of N. meningitidis wild-type (HT1125) and ΔgltT ΔgltM (HT1414) strains in AM, AM(−S), and AM(−S, −G) with 500 μM glutamate [AM(−S, +Glu)] at MOIs of 5, 50, and 500. Internalized bacteria were determined as bacteria recovered after gentamicin treatment. Each value is the mean and standard deviation of the mean (CFU per 10⁴ cells) from the results of at least four experiments. The open and solid bars indicate the numbers of HT1125 and HT1414 bacteria, respectively. Statistical analyses were performed with a two-tailed Student t test; *, P < 0.01; **, P < 0.05.