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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 ?
Evaluating the genotoxocity of surface water of Yangzhong city using the Vicia faba micronucleus test and the comet assay, Bull.
To measure the chromosomal radiosensitivity of SA breast cancer patients in a case-control study design with the micronucleus assay and the Metafer 4 scoring system.
The results obtained by micronucleus assay showed significantly a higher frequency of erythrocyte with micronuclei, blebbed nuclei, lobed, notched, heteropicnotic nuclei, binucleated and pear shape erythrocyte.
Sensitivity of the erythrocyte micronucleus assay: dependence on number of cells scored and inter-animal variability.
High level but not low-level occupational exposure to inhaled anesthetics is associated with genotoxicity in the micronucleus assay.
triacum Buisson, 1923, but the shape of macronucleus and the location of micronucleus are different.
Arnaboldi, "Human lymphocyte micronucleus genotoxicity test with mixtures of phytochemicals in environmental concentrations," Mutation Research--Genetic Toxicology and Environmental Mutagenesis, vol.
Validation of the mouse peripheral blood micronucleus assay using acridine orange supravital staining with urethane.
The Human MicroNucleus Project: an international collaborative study on the use of micronucleus technique for measuring DNA damage in humans.
6) The micronucleus test detects mutagenic substances that break chromosomes (clastogenic substances) or that interfere with mitotic spindle formation, thus altering the equitable distribution of chromosomes during cell division.
The Reconstructed Skin Micronucleus (RSMN) Assay is the first commercial offering of a Genetic Toxicology assay using three-dimensional tissue models.