macronucleus

The macronucleus contains hundreds of chromosomes, each present in many copies.

Each cell has one (often elongated) macronucleus and several micronuclei.

The macronucleus begins as a copy of the micronucleus.

There is apparently little, if any, DNA damage in the new macronucleus.

The macronucleus is long, and may be curved, horseshoe-shaped or twisted into a shape resembling a figure eight.

Climacostomum gigas is reported to have a compact, ovoid macronucleus.

Paramecium have two nuclei (a large macronucleus and a single compact micronucleus).

The macronucleus is large and sausage-shaped while the micronucleus is less prominent.

The macronucleus controls non-reproductive cell functions, expressing the genes needed for daily functioning.

These experiments indicated that the macronucleus, rather than the cytoplasm, is responsible for clonal aging.

Ciliates have cells that contain two nuclei: a macronucleus and a micronucleus.

A macronucleus (formerly also meganucleus) is the larger type of nucleus in ciliates.

The recent sequencing of the macronucleus genome should ensure that Tetrahymena will be continuously used as a model system.

They cannot survive without the macronucleus and cannot reproduce without the micro-nucleus.

The macronucleus may be moniliform (like a string of beads) or compact and oval, depending on the species.

This process is guided by long RNAs derived from the parental macronucleus.

This has two types of cell nuclei, a large, somatic macronucleus and a small, germline micronucleus.

The macronucleus of Climacostomum virens is normally long and wormlike (vermiform).

All ciliates except Karyorelictea have a dividing macronucleus.

During reproduction, the macronucleus splits by a type of amitosis, and the micronuclei undergo mitosis.

Trophozoites possess both a macronucleus and a micronucleus, and both are usually visible.

Usually only the macronucleus and sometimes cilia and contractile vacuoles are visible in the cyst.

The cell then divides in two, and each new cell obtains a copy of the micronucleus and the macronucleus.

For example, chromosome A may have 500 copies while chromosome B only has 5 copies in the macronucleus.

Thus, DNA damage in the macronucleus appears to be the cause of aging in Paramecium.