Electron micrographs of purified rSMD IB. A. IBs from cultures under controlled pH 7.5. B. IBs purified from uncontrolled pH cultures strategies. 1 h post-induction (left) (scale bars of 0.5 and 1.0 μm), 5 h post-induction (middle) (scale bars 2.0 μm), and 20 h post-induction (right) (scale bars 2.0 μm). Small IBs found at 5 h post-induction (B middle inset) (scale bar represents 0.1 μm). Examination of IBs produced after 20 h of induction (B right inset) (scale bar represents 200 nm).