The Regulation of Homopolar Doublets to Singlets in Glaucoma

Abstract

ABSTRACT. In the ciliate Glaucoma scintillans, the process of transformation of unbalanced homopolar doublets to singlets was investigated. Cells were fixed 1–3 days after inoculation and impregnated with silver according to the Chatton‐Lwoff technique. The two oral apparatuses (OAs) approached each other partly due to a loss of ciliary rows in one of the two components (semicells) consisting of a doublet. The contractile vacuole pore (CVP) in the narrow semicell (sc1) was lost at an early stage of regulation, while the position of CVP in the broad semicell (sc2) shifted toward the right after the loss of sc1. The sc1 of 20 row‐intervals in breadth was a transition point above which the sc1 was able to persist for awhile, and beneath which it was actively lost. There was no evidence for an independent effect of sc2 on the transformation of doublets to singlets. In cell division, an additional reversed oral primordium (sOP) was formed in unbalanced doublets, usually within a narrow sc1 of 11–20 row‐intervals. The position of the sOP was generally 4–6 row‐intervals distant from the right side of the oral meridian (OM1) with the cell's left OA. Most of the doublets with an sOP lacked an oral primordium in the OM1. No mature triplet with 2 normal OAs and an abnormal OA was found in these preparations. The pathway of regulation, the movement of the CVP, and the formation of an sOP are discussed.

Nuclear and Cortical Regulation in Doublets of Paramecium: II. When and How do Two Cortical Domains Reorganize to One?

“…However, doublets may instead meet the challenge and undergo a cortical reorganization into singlets, as first described in detail by Fauré‐Fremiet (1948) for Tetrahymena patula (formerly Leucophrys patula ). Such internal reorganization has since been studied in detail in oligohymenophorean ciliates, including the hymenostomes Tetrahymenathermophila (Frankel and Nelsen 1986; Nanney 1966; Nanney, Chow, and Wozencraft 1975; Nelsen and Frankel 1986) and Glaucoma scintillans (Suhama 1990), the peniculines P. tetraurelia (Kaczanowska and Dubielecka 1983; Prajer et al 1999; Sonneborn 1963; and this study), P. undecaurelia (this study) and Disematostoma colpidioides (Iftode, unpubl. observ.…”

“…The contractile vacuole and its pores always disappeared in the narrower semicell of unbalanced complete “ P. aurelia ” doublets (Prajer et al 1999), and of unbalanced Tetrahymena (Nelsen and Frankel 1986) and Glaucoma (Suhama 1990) doublets. The “exception that proves (i.e.…”

“…More striking and widespread is the transient appearance of a partially‐reversed third oral apparatus near the middle of sc1 in Tetrahymena patula (Fauré‐Fremiet 1948), T. thermophila (Nelsen and Frankel 1986), Glaucoma scintillans (Suhama 1990), and in the distantly related heterotrich Blepharisma japonicum (Kumazawa 1979). A similar interposition also occurs in the transient side‐by‐side doublets of the spirotrichs Stylonychia mytilus (Tuffrau and Totwen‐Nowakowska 1988), S. pustulata (Yano and Suhama 1991), and Paraurostyla weissei (Jerka‐Dziadosz 1983).…”

The Patterning of Ciliates1

“…Thus the regulating genically normal homopolar doublet had interposed a reversed cortical sector in the narrower semicell between two normal oral meridians. This phenomenon was observed repeatedly and reliably in Tetrahymena [40], and appeared in other ciliates as well (Blepharzsma [36], Glaucoma [50], Stylonychza [54,62]). In all of these triplets, the cortical structures of the central component are at least partially of a handedness opposite to that of the flanking two.…”