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Competition Among Homologous Polypeptide Pheromones of the Ciliate Euplotes raikovi for Binding to Each Other's Cell Receptors
Author(s) -
ORTENZI OLAUDIO,
LUPORINI PIERANGELO
Publication year - 1995
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.1995.tb01573.x
Subject(s) - pheromone , biology , sex pheromone , homologous chromosome , mating type , receptor , ciliate , microbiology and biotechnology , cell , mating , affinities , biochemistry , genetics , gene
. Purified preparations of the polypeptide pheromones Er‐1 and Er‐2 were obtained from type I and II cells of Euplotes raikovi , respectively, radiolabeled, and used to study their ability to compete with each other in binding to the same type I and II cells and to type × cells secreting Er‐10, another pheromone homologous to Er‐1 and Er‐2. It was shown that: 1) These radiolabeled pheromone preparations bind, with similar but not identical affinities, to cells from which they originate as well as to cells of the other types. 2) Every pheromone binding reaction can be completely inhibited by another homologous pheromone added in excess to cells. These results are discussed in relation to phenomena, common in ciliates, of instability of (homotypic) mating pairs formed between genotypically identical cells suspended with a foreign (nonself) pheromone.