Abstract
In diploid parthenogenesis of Norway spruce, specific nuclei were ontogenetically eliminated in cells programmed for cell death or apoptosis. Nuclear elimination was defined morphologically and biochemically for the degenerating ventral canal nucleus of egg-equivalents, and in differentiating suspensors of the axial tier of early embryos. Nuclei became pycnotic and disintegrated with the release of nucleoli and nuclear fragments into the cytoplasm. Enucleation in tubular cells of the axial tier was preceded by a reduction in the number of interphase nucleoli. Apoptosis was biochemically characterized by the activation of endonuclease activity that contributed to massive morphological changes in nuclei and ultimately to cell death. Endonuclease activity in individual nuclei was determined by a terminal deoxynucleotidyl transferase (TdT). This enzyme labeled the 3'OH ends of DNA, generated by DNA nicking with biotin-conjugated dUTP, for visualization with a secondary detection system using a colorimetric substrate for peroxidase. The TdT-mediated dUTP-biotin nick-end labeling (TUNEL) assay stained apoptotic nuclei red for the expression of endogenous endonucleases. The salvage of nuclear degradation products was postulated to enhance embryo survival, growth, and multiplication by cleavage polyembryony. By contrast, the egg-equivalent nucleus, proembryos, and the large and rounded nonapoptotic nuclei of the embryonal group fluoresced strongly with DAPI (4'-6-diamidino-2-phenylindole dihydrochloride). Nuclei also reacted blue with Giemsa in cells probed by the TUNEL assay.
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Claims 8
Claim · model-written summary
Specific nuclei were eliminated during diploid parthenogenesis.
- Taxon
- Norway Spruce
Picea abiest0 - Outcome
- specific nuclei were ontogenetically eliminatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Norway Spruce”
e0“In diploid parthenogenesis of Norway spruce, specific nuclei were ontogenetically eliminated in cells programmed for cell death or apoptosis”
Claim · model-written summary
Nuclei became pycnotic and fragmented.
- Taxon
- Norway SprucePicea abiest0
- Outcome
- Nuclei became pycnotic and disintegrated with the release of nucleoli and nuclear fragments into the cytoplasme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Norway Spruce”
e0“Nuclei became pycnotic and disintegrated with the release of nucleoli and nuclear fragments into the cytoplasm”
Claim · model-written summary
Tubular axial-tier cells lost interphase nucleoli before enucleation.
- Taxon
- Norway SprucePicea abiest0
- Organ / stage
- tubular cells of the axial tiere0
- Outcome
- reduction in the number of interphase nucleolie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Norway Spruce”
e0“Enucleation in tubular cells of the axial tier was preceded by a reduction in the number of interphase nucleoli”
Claim · model-written summary
Apoptosis involved endonuclease activation and cell death.
- Taxon
- Norway SprucePicea abiest0
- Outcome
- activation of endonuclease activitye0
- Qualifier
- massive morphological changes in nucleie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Norway Spruce”
e0“Apoptosis was biochemically characterized by the activation of endonuclease activity that contributed to massive morphological changes in nuclei and ultimately to cell death”
Claim · model-written summary
TUNEL stained apoptotic nuclei red.
- Taxon
- Norway SprucePicea abiest0
- Outcome
- stained apoptotic nuclei rede0
- Value
- rede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Norway Spruce”
e0“The TdT-mediated dUTP-biotin nick-end labeling (TUNEL) assay stained apoptotic nuclei red for the expression of endogenous endonucleases”
Claim · model-written summary
Nuclear degradation products were postulated to improve embryo survival, growth, and multiplication.
- Taxon
- Norway SprucePicea abiest0
- Outcome
- enhance embryo survival, growth, and multiplicatione0
- Qualifier
- salvage of nuclear degradation productse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Norway Spruce”
e0“The salvage of nuclear degradation products was postulated to enhance embryo survival, growth, and multiplication by cleavage polyembryony”
Claim · model-written summary
Nonapoptotic embryonal nuclei fluoresced strongly with DAPI.
- Taxon
- Norway SprucePicea abiest0
- Outcome
- fluoresced strongly with DAPIe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Norway Spruce”
e0“the egg-equivalent nucleus, proembryos, and the large and rounded nonapoptotic nuclei of the embryonal group fluoresced strongly with DAPI”
Claim · model-written summary
Nuclei reacted blue with Giemsa in TUNEL-probed cells.
- Taxon
- Norway SprucePicea abiest0
- Outcome
- reacted blue with Giemsae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Norway Spruce”
e0“Nuclei also reacted blue with Giemsa in cells probed by the TUNEL assay”