FIG. 6.

Modulation of bacterial autoaggregation via controlled production of the Ag43 protein. The different strains were grown overnight in LB medium with either 0, 0.4, and 1% glucose (glu) or concentrations of arabinose (ara) ranging from 0.004 to 1%. (A and B) The aggregation of MG1655catRExBADflu increased with the arabinose concentration. After growth cells were diluted to an OD₆₀₀ of 2.5 in a 3-ml culture, and the autoaggregation of each strain was assessed after incubation for 24 h at room temperature by capturing images of the tubes (A) and determining the OD₆₀₀ of the upper part of the culture in each standing tube (dashed line) (B). The aggregation tests were performed in triplicate. (C) Ag43 production by MG1655catRExBADflu can be modulated by increasing arabinose concentrations. For each culture the equivalent of 0.2 OD₆₀₀ unit was loaded on a sodium dodecyl sulfate-10% polyacrylamide gel electrophoresis gel. Immunodetection was performed by using a polyclonal rabbit antiserum raised against the α domain of Ag43. Ø indicates that no sugar was added.