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(invertebrate zoology)
The smaller, reproductive nucleus in multinucleate protozoans.



in infusorians, the smaller (generative) nucleus. The micronucleus is usually diploid and divides by mitosis; however, during the sexual process in infusorians (conjugation), it divides meiotically and gives rise to sexual nuclei or pronuclei. During the vegetative period, the genetic apparatus of the micronucleus remains inactive, does not synthesize ribonucleic acid, and has no influence on the phenotype of the organism.

References in periodicals archive ?
A standard testing panel would include: ocular irritation, skin irritation, Ames and Micronucleus tests, skin sensitization and phototoxicity (if relevant)
Histological changes and micronucleus induction in the zebra mussel Dreissena polymorpha after paraquat exposure.
Gentronix now offers both Ames and in vitro micronucleus testing under GLP using the most up to date OECD protocols to generate studies ready for incorporation into regulatory dossiers.
Sensitivity of the erythrocyte micronucleus assay: dependence on number of cells scored and inter-animal variability.
Comparison of genomic damage caused by 5nitrofurantoin in young and adult mice using the in vivo micronucleus assay.
Several studies [10-12] indicated that females might tend to have significantly higher micronucleus frequency than males.
25 Concentration Treatment Micronucleus Giant [micro]g/ml Duration cells (hour) No.
Instead, they're marooned elsewhere within the cell and become wrapped in their own membrane, forming a micronucleus.
In the micronucleus assay, femoral bone marrow smears from mice orally treated with E.
Radiation-induced micronucleus formation and DNA damage in human lymphocytes and their prevention by antioxidant thiols.