kappa particles

kap·pa par·ti·cles

inheritable cytoplasmic symbionts, once thought to be particles mainly or exclusively of DNA, occurring in some strains of Paramecium; capable of producing a product lethal to other strains.

kappa particles

the bacteria that inhabit the cytoplasm of the ciliate Paramecium aurelia. Kappa-free Paramecia are sensitive to toxins produced by the particles, dying when exposed to them, after CONJUGATION. Kappa carriers (called killer stocks) are immune to the toxin.
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