Z Disc Ultrastructure in Scutal Depressor Fibers of the Barnacle

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Science  03 Apr 1970:
Vol. 168, Issue 3927, pp. 127-128
DOI: 10.1126/science.168.3927.127


The ultrastrlucture of Z discs in nonglycerinated, striated muscle fibers of the barnacle Balanus nubilus Darwin was examined in contracted, resting, and stretched preparations. At all sarcomnere lengths, the Z discs are perforated sheets comprised of "Z rimns" and "Z perforations," extending continuously across the myofibril; the dimensions of the rims and perforations change with changes in sarcomere length. Accordingly, with shortening of the sarcomere, there was an accompanying decrease in the transverse width of the Z rims and an increase in the diameter of the Z perforations.

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