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Cortical Structure in Nondividing and Cortical Morphogenesis in Dividing Oxytricha fallax * †
Author(s) -
GRIMES GARY W.
Publication year - 1972
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1972.tb03498.x
Subject(s) - primordium , biology , morphogenesis , anatomy , process (computing) , genetics , gene , operating system , computer science
SYNOPSIS. Light‐ and electronmicroscopic observations of nondividing Oxytricha fallax revealed a high degree of cortical complexity in this species and provided much additional detail to previous descriptions of hypotrich ciliates. By the same microscopic methods, the morphogenetic pattern of O. fallax was found to be similar to that of other hypotrich genera with regard to the formation of oral primordium in association with cirri and to the incorporation of specific cirri into cirral primordia. There is no donation of any cirral part to the oral primordium, but cirri involved in cirral primordia formation appear to be donated fully to these primordia. Attainment of final form and size of the oral primordium and new cirri is a multistep process. Alignment of kinetosomes to form membranelles occurs first in pairs, the immature membranelles containing only 2 rows of kinetosomes. The 3rd and 4th rows are added by production of new kinetosomes from right to left on the anterior edge of each membranelle. Cirral development, likewise, is not completed until individual new cirri are distinguishable, new kinetosomes being added as the cirri move to their final locations on the organism's surface. The cirral resorption process also is reported briefly. Means of experimental analysis of the possible role of individual cortical structures in morphogenesis is discussed.