Effects of histones on mitochondrial function and ultrastructure.

<p>Panel <i>A</i>: mitochondrial membrane potential. Mitochondria were suspended in measurement medium supplemented with 0.5 µM TMRM. Succinate (<i>Suc</i>) was added to energize the mitochondria followed by 1 µM tBID (<i>tBID</i>), the indicated concentration of histone H1.2 (<i>H1.2</i>), 10 µM histone H2A (<i>H2A</i>), 10 µM histone H2B (<i>H2B</i>), 5 µM histone H3 (<i>H3</i>), or 5 µM histone H4 (<i>H4</i>). The <i>asterisk</i> indicates anoxia. Panel <i>B</i>: mitochondrial ultrastructure. Mitochondria suspended in measurement medium were incubated with histones for 30 min and then processed for transmission electron microscopy. The primary magnification is 50 000× and the scale bar is 200 nm. Panel C: light scattering. Mitochondria were suspended in measurement medium containing succinate. Histones were added as indicated. Trace <i>a</i> and <i>b</i>, 5 µM histone H1.2, in trace <i>b</i> the medium was supplemented with 1 µM cyclosporin A, trace <i>c</i> 10 µM histone H2A, trace <i>d</i>, 5 µM histone H3, trace <i>e</i>, 10 µM histone H2B, and trace <i>f</i>, 5 µM histone H4.