L 1 l cysteine

Tannerella forsythia ATCC 43037 (American Type Culture Collection, USA) and defined T9SS mutants (see below) were grown in 37 g L⁻¹ of Brain-Heart-Infusion (BHI) liquid media (Oxoid, UK), containing 5 g L⁻¹ yeast extract (Oxoid), 0.5 g L⁻¹ L-cysteine (Sigma, Austria), 2.5 μg mL⁻¹ hemin (Sigma), 2.0 μg mL⁻¹ menadione (Sigma), 10 μg mL⁻¹N-acetylmuramic acid (Carbosynth, UK) and 5% (v/v) horse serum (Life Technologies, Austria), under anaerobic conditions at 37°C for 4-7 days. For cultivation of T. forsythia wild-type and mutants on BHI agar plates (0.8% w/v), the amounts of L-cysteine, hemin, and N-acetylmuramic acid were doubled and plates were incubated under anaerobic conditions in an anaerobic jar (AnaeroJar; Oxoid) at 37°C. Media were supplemented with gentamycin and erythromycin at a concentration of 200 μg mL⁻¹ and 5 μg mL⁻¹, respectively, when appropriate.
Escherichia coli strains were grown under standard conditions in Luria-Bertani (LB) medium supplemented with 100 μg mL⁻¹ ampicillin, when appropriate. P. gingivalis W83 is used as a reference strain for comparison with predicted components of the T9SS in T. forsythia ATCC 43037.