Cytokinesis of the binucleate zoosporangia of Allomyces macrogynus

Cleavage of cytoplasm within the oligonucleate zoosporangia ofAllomyces macrogynus

“…Development of cleavage membranes on the cleavage planes.-Studies on the zoosporangia of A. macrogynus clearly indicated that the cleavage membranes developed from the plasma membranes (Fisher et al 2000, Ji et al 2010. This study on the oligonucleate zoosporangia also reported the origin of cleavage membranes from the plasma membrane.…”

“…During the development of a single cleavage plane within a binucleate zoosporangium, ingression of cleavage membranes into the region of the nuclear axis was delayed until the cleavage membranes occupied more than half of the area of the entire cleavage plane (Ji et al 2010). During the development of two separate cleavage planes, or three cleavage planes within a zoosporangium, ingression of cleavage membranes into the region of the nuclear axis was severely delayed in one of the two or in two of the three cleavage planes respectively.…”

“…Culture conditions and induction of oligonucleate zoosporangia.-Conditions for the culture and induction of zoosporangia of A. macrogynus (strain Burma 3-35 of Emerson) were described by Ji et al (2010). Zoospores were incubated in PYG broth 2.5-4 h at 33 C, and the resulting thalli were washed with and maintained under sterile dilute salts solution (DS) (Machlis 1953) for 2 h at 33 C. These thalli again were shifted to PYG broth at 39 C and incubated 2-4 h. Cleavage of cytoplasm was induced after another shift from PYG at 39 C to DS at 33 C. Inhibitors (5 mg/mL nocodazole (Sigma, St Louis, Missouri), 5 mg/mL cytochalasin D (Sigma), were added to DS at 33 C after shift from PYG at 39 C.…”

“…A study on the cytokinesis of the binucleate zoosporangia of A. macrogynus (Ji et al 2010), however, suggested that the cleavage membranes on the cleavage plane ingress asymmetrically from the plasma membrane but the segmentation of cytoplasm is completed by the fusion of cleavage membranes with the plasma membrane. Also, the positions of the two nuclei seemed to affect the development of cleavage membranes on the cleavage plane as well as the position of the cleavage plane.…”

“…Cleavage of cytoplasm within the zoosporangia had been studied by numerous microscopy authorities (Barron andHill 1974, Hyde et al 1991a) and the use of cryofixation and freeze substitution in electron microscopy has resulted in improved preservation of cleavage membranes and renewed interests on the cytokinesis of the zoosporangium (Hyde et al 1991b). The cleavage of cytoplasm within the zoosporangia of Allomyces macrogynus, a member of true zoospore fungi (James et al 2006), has been studied intensively, and these studies helped to elucidate the basic patterns of cleavage membrane development and the roles of cytoskeletons on cytokinesis (Lowry and Roberson 1997, Lowry et al 1998, Fisher et al 2000, Lowry et al 2004, Ji et al 2010.…”