FIG. 4.

Alternation of the S-layer networks on the parental strain according to the growth phase. The parental 9131 strain (Sap⁺ EA1⁺) was subjected to double-immunogold labeling during the exponential (a and b) and stationary (c) phases. Deflated bacteria were incubated with mouse anti-Sap and rabbit anti-EA1 antibodies. Binding was revealed with 10-nm gold-conjugated anti-mouse antibodies and 15-nm gold-conjugated anti-rabbit antibodies. Scale bars, 500 (a) and 100 nm (b and c). The Sap S-layer can be seen to wind around the axis of the bacterium in two independent images. The areas in panel a not covered by the Sap array are delineated, and the labeled Sap array is visible in the magnified figure (b). The few 15-nm particles revealing EA1 protomers are indicated by arrows in panel b. (c) During stationary phase, the emergence of the labeled EA1 array (E) destabilizes the labeled Sap array (S).