FIG. 8.

Size fractionation of pigment and ferric reductase activity of L. pneumophila. Aliquots of acid-precipitated material obtained from CDMP cultures of wild-type strain 130b were centrifuged through filter units having a molecular mass cutoff of 3, 10, 30, or 50 kDa, and then the pigmentation and ferric reductase activity in each filtrate were quantified as described in the text. The results are presented as the percentage of pigment (black bars) and ferric reductase activity (white bars) in each of the fractionated filtrates compared to the starting material. The data presented are the means and standard deviations from triplicate cultures.