macronucleus


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Related to macronucleus: oral groove

mac·ro·nu·cle·us

(mak'rō-nū'klē-ŭs),
1. A nucleus that occupies a relatively large portion of the cell, or the larger nucleus where two or more are present in a cell.
See also: micronucleus (2). Synonym(s): meganucleus
2. The larger of the two nuclei in ciliates, which governs vegetative metabolic functions and not reproduction.
See also: micronucleus (2). Synonym(s): somatic nucleus, trophic nucleus, trophonucleus

macronucleus

/mac·ro·nu·cle·us/ (-noo´kle-us) the larger of two types of nuclei when more than one is present in a cell.

macronucleus

(măk′rō-no͞o′klē-əs, -nyo͞o′-)
n. pl. macronu·clei (-klē-ī′)
The larger of two nuclei present in ciliate protozoans, which controls nonreproductive functions of the cell, such as metabolism.

mac′ro·nu′cle·ar adj.

macronucleus

[-no̅o̅′klē·əs]
Etymology: Gk, makros + L, nucleus, nut
1 a large nucleus that occupies a relatively large portion of the cell.
2 (in protozoa) the larger of two nuclei in each cell, governing cell metabolism and growth as opposed to the micronucleus, which functions in sexual reproduction.

mac·ro·nu·cle·us

(mak'rō-nū'klē-ŭs)
1. A nucleus that occupies a relatively large portion of the cell, or the larger nucleus where two or more are present in a cell.
2. The larger of the two nuclei in ciliates, which governs vegetative metabolic functions and not reproduction.
See also: micronucleus (2)

macronucleus

or

meganucleus

the larger of two nuclei found in some PROTOZOANS, that is concerned with cell division (see MICRONUCLEUS). It disappears during CONJUGATION and is afterwards reformed from material of micronuclear origin (from the zygote nucleus). It appears to have mainly vegetative functions.

macronucleus

the larger nucleus when there are two in the cell.
References in periodicals archive ?
triacum Buisson, 1923, but the shape of macronucleus and the location of micronucleus are different.
It then creates a new macronucleus that takes over for the old one.
Another mystery is the unscrambling for the macronucleus of genes that had been shattered into pieces and scattered out of order in the micronucleus.
CAVALIER-SMITH; I don't think that you should call the DNA that is eliminated in the macronucleus "junk DNA," because that designation begs the question of whether it has a non-coding function.
It might have some specific function in the micronucleus, but the DNA is transcriptionally inert in the micronucleus and absent from the macronucleus.
Have you taken an unscrambled gene and put it in the macronucleus to determine if it is functional?
LANDWEBER: Hans Lipps's lab in Witten, Germany, has successfully injected DNA into the developing macronucleus and shown that it is partially processed and stably retained in the macronucleus (2), but we have not yet tried scrambled genes in any form.
When food is plentiful, tetrahymena operates under the command of the macronucleus and splits repeatedly into identical copies of itself.
Micronucleus A small nucleus closely associated with the macronucleus in ciliates.
They had a band-like macronucleus (the big backward "C").