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M H Stromer

Publications and source records attributed to M H Stromer.

59 records · Page 4Linked to original sources
PubMed1969

The effect of various protein fractions on Z- and M-line reconstitution.

Extraction of thin, glycerinated bundles of rabbit psoas muscle with a low ionic strength solvent results in removal first of M lines and then of Z lines. When these extracted myofibrillar bundles are allowed to interact, at adjusted ionic conditions, with the dilute myofibrillar extract or with the fractions obtained at 40% ammonium sulfate saturation from either the myofibrillar extract or from the Bailey extract of natural actomyosin, reconstitution of Z lines occurs. The ammonium sulfate fraction from the Bailey extract of natural actomyosin restores the tetragonal lattice structure of the Z line. Other structural features such as I-band tufts or cross-bridges, M lines and H-zone binding also occur with some of the proteins used for recombination. Although it has not yet been possible to identify exactly the protein(s) constituting the Z line, it appears unlikely that tropomyosin or troponin alone is the major protein of the Z line. A more likely candidate is alpha-actinin or a combination of alpha-actinin with another protein(s). In addition, this study demonstrates that basic morphological differences exist between cross-sections through the Z-line lattice and cross-sections through tropomyosin crystals.

Animals↗
PubMed1967

Morphology of rigor--shortened bovine muscle and the effect of trypsin on pre- and postrigor myofibrils.

Bovine semitendinosus muscles were sampled immediately after death, after 24 hr postmortem with storage at 2 degrees , 16 degrees , or 37 degrees C, and after 312 hr postmortem with storage at 2 degrees and 16 degrees C. A biopsy technique was used to prevent shortening during glutaraldehyde fixation. Postfixation in osmium tetroxide was followed by embedding in an Epon-Araldite mixture. Bovine muscle was supercontracted after 24 hr storage at 27deg; but was only slightly contracted after storage at 16 degrees for 24 hr. Muscle held at 37 degrees for 24 hr was slightly less supercontracted than the 2 degrees muscle. Striking similarities existed between muscles stored at 16 degrees and at 2 degrees C for 312 hr. Both were slightly shortened with narrowed I bands and an area of increased density, probably due to overlap of thin filaments in the middle of the A band. Postmortem shortening was accompanied by banding-pattern changes similar to those predicted for contracting muscle by Huxley and Hanson's sliding filament model. Treatment of myofibrils with 0.05% trypsin resulted in a rapid loss of Z lines and, in supercontracted myofibrils, caused a return of the banding pattern of resting muscle.

Animals↗