Corticotypes in Tetrahymena pyriformis

Abstract

Strains of syngen 1 manifest extensive structural variation affecting most of the gross features revealed by silver impregnation techniques. The variations are rationalized by evidence for an association between the individual variables and the compoundness of the total cortical pattern. The cortical compoundness is indicated by the number of ciliary rows, which in these strains may vary from about 16 to 35. For ease in correlational analysis, each of the discrete classes is designated as a morph (corticotype) in a polymorphic array. Each corticotype has a characteristic pattern and distribution of variation for a number of cortical properties. These include numbers and positions of contractile vacuole pores, numbers of postoral meridians, numbers of oral apparatuses, and patterns of stomatogenesis. Studies on corticotype stability demonstrate that the various cortical patterns are capable of being perpetuated during fission with different degrees of reliability, but that under the growth conditions employed, a modulation occurs toward corticotype 18.