Factors involved in the sensitivity of Stentor to colchicine, lumicolchicine, and vinblastine sulfate.

Oral regeneration by the ciliate Stentor coeruleus is inhibited by colchicine (Cc), but only at a relatively high concentration (0.9 mM); moreover, regeneration is inhibited by an even lower concentration of lumicolchicine (LCc) (0.2 mM).

Insensitivity of ciliary outgrowth in situ by Stentor to far UV.

Outgrowth of membranellar cilia in situ by the ciliate protozoan Stentor coeruleus is not affected by either far UV or by postirradiation exposure to cycloheximide, while UV does affect the outgrowth of membranellar cilia during the more elaborate process of oral regeneration in this ciliate, and cycloheximide prolongs the UV effect. These results suggest that direct damage to outgrowing ciliary shafts cannot explain the UV sensitivity of oral regeneration.

Sensitization of bleached Stentor to far UV.

Stentors are more sensitive to far UV-induced delay of oral regeneration following bleaching of their UV-absorbant cortical pigment granules. This finding supports a subcortical location of UV-sensitive sites.

Microtubule dynamics and glutathione metabolism in phagocytizing human polymorphonuclear leukocytes.

Glutathione oxidants such as tertiary butyl hydroperoxide were shown previously to prevent microtubule assembly and cause breakdown of preassembled cytoplasmic microtubules in human polymorphonuclear leukocytes. The objectives of the present study were to determine the temporal relationship between the attachment and ingestion of phagocytic particles and the assembly of microtubules, and simultaneously to quantify the levels of reduced glutathione and products of its oxidation as potential physiological regulators of assembly. Polymorphonuclear leukocytes from human peripheral blood were induced to phagocytize opsonized zymosan at 30 degrees C.