| The Z-band is the structure in striated muscle which connects adjacent sarcomeres and transmits the force of contraction between sarcomeres. In vertebrate striated muscle, the Z-band is capable switching between two structurally distinct states, called small-square and basketweave after their appearance in transverse sections. This work examines the small-square to basketweave transition of the vertebrate striated muscle Z-band using mechanics, electron microscopy and X-ray diffraction. All experiments used single skinned fibers from rabbit psoas muscles. For the mechanics experiments, force produced by and stiffness of a fiber upon exposure to experimental solutions was recorded with a tension transducer. All electron microscopy samples were chemically fixed and examined in transverse sections. Electron micrographs were analyzed by computed Fourier transform to determine the average distance between filaments within the muscle. X-ray diffraction experiments were carried out to determine the distance between filaments in fibers that were not fixed for electron microscopy. Under standard conditions of 38... |
