Intersyngenic variations in the esterases of axenic stocks of Paramecium aurelia

Abstract

The esterase isozymes were surveyed in axenic stocks of syngens 1, 2, 4, 5, 6, and 8 of Paramecium aurelia by starch gel electrophoresis. In paramecia there appear to be four types of esterases which are clearer in axenie than in baeterized stocks. Each type differs in its substrate specificity and/or its response to the inhibitor eserine sulfate. Minor variations in type D esterases sometimes occur in different extracts of the same stock and may result from changes in the temperature of growth of the cells or growth cycle differences. Differences in the mobility of the A, B, or C (eathodal) types of esterases may occur in different syngens. They also occur for the A and B types among stocks within a syngen, but the frequency is low, except in the case ofsyngen 2. Since each of the types of esterases varies independently, at least four and possibly more genes appear to specify the esterases in the species complex. Some pairs of syngens vary in their eleetrophoretic positions for all types of esterases. Other pairs have identical zymograms. This observation suggests that some syngens may differ from each other by as many as four esterase genes, while others may not differ at all. The difference between P. aurelia and Tetrahymena pyriformis in the degree of intrasyngenie variation observed for enzymes is discussed in relation to other types of characters, the organization of the genetic material in the macronueleus, the presence of symbionts, and their breeding systems. It is suggested that enzyme variation is achieved by the action of different selective forces in these two groups of ciliated protozoa.

Electrophoretic Analysis of Evolutionary Relationships in Tetrahymena

“…The present report provides further support on the basis of variations of isozyme patterns which also provide a means of identifying the syngens and examining their relationships. Allen and Weremiuk, 1971;Allen andGibson, 1971, 1975;Allen and Golembiewski, 1972;Borden et aI., 1973bBorden et aI., , 1973c. Allen and Weremiuk, 1971;Allen andGibson, 1971, 1975;Allen and Golembiewski, 1972;Borden et aI., 1973bBorden et aI., , 1973c.…”

Genetic determination of esterases of syngens 1 and 8 in Paramecium aurelia

“…They are stocks 299 and 138 of syngen 8 and stocks 540 and 90 of syngen 1. Their geographical origins are indicated elsewhere (Allen and Gibson, 1971). They are maintained in test-tube culture by weekly iso-.…”

“…With the discovery of gene control of these enzymes we have other gene markers for comparing the syngens of Paramecium in terms of gene and protein homologies (Allen and Gibson, 1971). 2.…”

“…The esterases and some mitochondrial enzymes of different stocks and syngens of Paramecium have been compared (Tait, 1970a, b;Allen, Byrne and Cronkite, 1971;Allen and Gibson, 1971). There was a general lack of variation between the esterases and mitochondrial enzymes of the stocks within a syngen although variations between syngens were common.…”

“…The A esterases react with oc-naphthyl propionate, but not with cc-naphthyl butyrate, B with both substrates but more readily with the propionate, type C with butyrate more rapidly than propionate and type D esterases split both substrates to the same extent. The A esterases are also isozymic and show greater esterase variation between syngens than do the B esterases or the C (Allen and Gibson, 1971). In this paper we will study the following variations:…”