Protoplasmic clotting in isolated muscle fibers

Abstract

FOUR FIGURESChanges in the colloidal state of protoplasm provide an important index to the nature of intracellular events. Certain of these changes appear to be fundanlentally identical with the surface precipitation reaction (s.p.r.) which occurs ~7lle11 the membrane of a cell is ruptured, and the cellular contents are exposed to the external medium. The capacity to show this reactioii seeins to be a general property of protoplasm, and it has been demonstrated, under the proper conditions, in many kinds of cells. A substantial amount of evidence suggests that it is the result of the same kind of process as that which causes the gelation of the interior of a cell following stimulation and, also, that it iiivolves a mechanism similar to that operating in the coagulation of blood and other kinds of biological fluids, such as milk. ( P o r a more detailed description and discussion of the s.p.r. and references to experiments on it, see Heilbrunn, '43.)Usually tlie s.p.r. is produced by crushing or tearing a cell. These methods unfortunately tend to permit the use of the reaction only as a qualitative test; that is, it either o c c~~r s o r does not occur in the presence of a given medium. Evidence concerning the degree of effect under given experimental . A dissertation submittcd to the facultp of the Dqxirtment of Zoologp of the Univcrsity of Pennsylvania in partial fulfillment of the requirements for the degree of Doctor of Philosophy. The research was supported in part by :I grant from the Roekefeller Youudatioii administcred by Dr. L. V. Heilbrunn. 359

Muscle

“…Furthermore, the author is not aware of any evidence indicating, at least for frog muscle , that physiological contraction is maximal at a critical temperature of about 16° to 18°C. Another important point of difference is found in the result of Heilbrunn and his students (65,66) that the calcium ion, intracellularly introduced, practically specifically activates the protoplasmic clotting of isolated surviving single muscle fibers of the frog. It is beside the point that these authors attribute the dotting to a surface precipitation lleaction and not to a synaeresis.…”

“…In this regard, we' note the findings of Heilbrunn and his students (65,66) that potassium has little effect on the shortening or clotting of muscle cytoplasm, either when injected into the fiber or allowed to act by diffusion through the cut ends. But these experiments were done on resting fibers, and it would be of great interest for the comprehension of contractility to study the effect of electric stimul.…”

Membrane healing and restoration of contractility after mechanical injury in isolated skeletal muscle fibers of the frog.

“…In this and in other fibers left in Ringer's solution for several hours, the clustering of contracted myofibrils progressed until there was similar deterioration all along the fiber. This probably corresponds to plug formation and its advance (2,3). Interestingly, the damage to the surface membrane eventually stops growing and the empty spaces between the clusters of contractile material are then surrounded by a sarcolemmal tube (13).…”

The Effects of Calcium on Isolated Arthropod Muscle Fibers

“…Moreover, the protoplasm of muscle like that of other types of cells can and does undergo a gelation similar to the clotting of blood. For a description of the clotting reaction see Speidel (1938) ; Heilbrunn and Wiercinski (1947) ; Woodward (1948). In marine eggs and protozoa, calcium and thrombin-like substances can cause protoplasm to clot (Heilbrunn and Daugherty, 1932).…”

“…Here then is a system which can be studied. Woodward (1948) has studied the clotting properties of the vertebrate muscle. With few exceptions (for example, see Yaeger and Hager, 1934;Proctor, 1952) there is no available information concerning the effects of calcium on isolated invertebrate muscle fibers.…”