Cell patterning.

  • Symposium on Cell Patterning (1974 : London, England)
Date:
1975
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Cell patterning. Source: Wellcome Collection.

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    Fig. 1 . Diagrams of the arrangement of ciliature on the ventral and dorsal surfaces of Euplotes minuta. The dark masses on the ventral surface represent groupings of cilia (cirri and membra- nelles), whereas the dots represent sites of single short cilia. The cell here depicted has 9 ciliary rows. Cells with a smaller or greater number of rows show the same pattern of arrangement of rows, with wider or narrower spacing of rows. surface of the ciliate cell, and I shall deal with these by discussing a small and somewhat arbitrary selection of examples of morphometric, genetic, and micro- surgical investigations carried out on two ciliate species, Euplotes minuta and Paraurostyla (formerly Urostyla ) weissei. Other examples, mainly micro- surgical analyses, are discussed in a longer communication dealing with similar issues (Frankel 1974a). DESCRIPTIVE PRELUDE The specific morphological entities with which we are concerned are the ciliary rows and the cirri. The arrangement of these structures on the surface of non dividing Euplotes minuta is shown in Fig. 1. The organisms are dorsoventrally flattened and nearly oval in contour. Seven to ten longitudinal rows of stubby cilia are sparsely distributed over the dorsal surface and lateral edges. The ventral surface is covered by clustered groupings of very long cilia which collectively make up the feeding and locomotor systems of the cell. The feeding system is mainly made up of parallel bands of plate-like membranelles, while the locomotor system is composed of a number of groupings of cilia termed cirri. Each cell typically contains 19 cirri, disposed in a constant arrangement shown in Fig. 1. Cell division is transverse, and all ciliary systems are duplicated prior to division, providing complete and (usually) identical organelle sets for both