Fibrillar Structures in the Cytoplasm of Chaos Chaos

Although a number of studies of the finc structure of fixed amcbae have appeared (Pappas, 1959; Mercer, 1959; Roth, 1960; Brandt and Pappas, 1962), fibrillar structures in the cytoplasm have not been reported. This is surprising in view of thc fact that several current theories of ameboid movemcnt postulate the cxistence of contractile and hence presumably fibrillar material. This discrepancy bctween what is thought to cxist in living amebae and what has so far been found in fixed specimens has recently been emphasized (Goldacre, 1961; Pitelka, 1963). Furthermore, thcre is mounting evidence from other Wpes of studics that contractilc structures exist in amebae. To cite only a few cxamples, Kriszat (1949) and Goldacre and Lorch (1950) found that adenosine triphosphate produced characteristic changes in thc cytoplasmic consistcncy of amebae. Simard-Duquesne and Couillard (1962) reported that a glycerinated ameba preparation contracted upon addition of adenosine triphosphatc and magncsium ion. Most recently, Wolpert, Thompson, and O'Neil l (1964) have provided electron microscope evidence for fibrillar material in preparations of centrifuged ameba cytoplasm induced to gelate by addition of adenosine triphosphate. The present communicat ion reports the finding of extensive areas of fibrillar material in sections of amebae fixed after exposure to Alcian Blue, a dye which binds irreversibly to the cell surface and induces pinocytosis at room temperature.