Identification of the Basal Bodies and Kinetodesmal Fibers in Living Cells of Paramecium tetraurelia Sonneborn, 1975 and Paramecium sonneborni Aufderheide, Daggett & Nerad, 1983¹

Abstract

Critical use of Nomarski DIC optics and a rotocompressor permits basal bodies and kinetodesmal fibers to be visualized in the cortices of living Paramecium tetraurelia and Paramecium sonneborni. The identification of these structures is confirmed by the correspondence of the images obtained by DIC optics of living cells and by brightfield optics of fixed cells stained by the Fernández-Galiano silver technique. Examination of cells carrying cortical inversions (portions of the cortex rotated 180 degrees) shows that inverted regions may be identified and distinguished from normal regions by the orientation of the kinetodesmal fibers of the kinetids (cortical units) within the kineties (ciliary rows). This demonstrates that both the asymmetry and the polarity of each cortical unit may be assessed in the living cell. This technique has useful applications in the study of morphogenesis and patterning in living cells and for the screening of mutations and variants conferring altered cortical phenotypes.

Refinements of and commentary on the silver staining techniques of Fernández-Galiano

“…Consistent with other descriptions of Fernández-Galiano staining (Fernández-Galiano 1976, 1994, Foissner 1991, 2014), my protocol reliably stains the basal bodies, parasomal sacs and kinetodesmal fibers of the cell cortex (Allen 1971, Aufderheide 1986, Cohen and Beisson 1988) (Fig. 1).…”

“…Properly done, the technique demonstrates cells with delicately stained cortical structures that enable critical analysis of cytoskeletal and membranous components and their morphogenesis for systematics analysis, and cell and developmental studies (Aufderheide 1986, 1999, Foissner 1991, Ma et al 2003, Small et al 2005, Pérez-Uz et al 2010, Fokam et al 2011). Unlike fluorescent antibody labeling, Fernández-Galiano staining can be performed quickly and requires no special reagents or microscopy equipment.…”

The Mother Centriole Plays an Instructive Role in Defining Cell Geometry

“…However, each cortical unit contains not only a cilium and centrioles, but also kinetodesmal fibers, trichocysts, striated bands, infraciliary lattice fibers, the “fork/bone node” [48], and an apparently self-duplicating oriented structure called the “post” [49]. Because inversion of rows simultaneously inverts the orientation of all of these other structures [50], it is not possible to determine which of the substructures within the cortical unit serves as a coordinating local signal to orient the other structures during formation of new cortical units in cell division.…”

Directed Positioning of Micronuclei in Paramecium tetraurelia with Laser Tweezers: Absence of Detectible Damage After Manipulation

“…Paramecia were placed in a 0.5-mm-diameter droplet on the platform of a rotocompressor of local design and manufacture [6]. While viewing the cells under low power, the rotocompressor was adjusted to immobilize the cell with the minimum distortion possible.…”

“…While viewing the cells under low power, the rotocompressor was adjusted to immobilize the cell with the minimum distortion possible. With care, immobilized cells may be observed for up to 30 min without apparent damage from the flattening, and they may be recovered for subsequent culturing [6]. The laser beam was fixed in the specimen plane and the cell was moved relative to the beam using the mechanical stage control.…”