Abstract
DNA synthesis during the early stages of callus formation was examined in carrot root slices cultured on an agar medium containing 2,4-D. During the first 12 hr of culture, only a low level of 3H-thymidine was incorporated into DNA, after which the incorporation rapidly increased and reached a maximum at about 48 hr, then gradually decreased. CsCl density centrifugation of total tissue DNA indicated that a satellite DNA with a buoyant density of about 1.712 g/ml replicates in the early phase of the DNA synthetic period, then the main band DNA with a buoyant density of 1.695–1.700 g/ml starts its replication and continues to be produced throughout the synthetic period. The labeled satellite DNA, as well as the labeled main band DNA, was localized mainly in the subcellular fraction of 1,000 × g sediments obtained from tissue homogenates. The patterns of cellular localization were not modified by the addition of Triton X-100 to the initial homogenates. A considerable portion of the labeled satellite DNA was found in nuclease-resistant chromatin subunits after limited digestion of the isolated chromatin with micrococcal nuclease.
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Claims 6
Claim · model-written summary
DNA label incorporation was initially low, then rose to a 48 hr maximum and declined.
Not reportedTaxon
Verbatim
e0“During the first 12 hr of culture, only a low level of 3H-thymidine was incorporated into DNA, after which the incorporation rapidly increased and reached a maximum at about 48 hr, then gradually decreased.”
Claim · model-written summary
Satellite DNA replicated in the early DNA synthesis phase.
Not reportedTaxon
Verbatim
e0“a satellite DNA with a buoyant density of about 1.712 g/ml replicates in the early phase of the DNA synthetic period”
Claim · model-written summary
Main band DNA began replication after satellite DNA and continued throughout synthesis.
Not reportedTaxon
Verbatim
e0“then the main band DNA with a buoyant density of 1.695–1.700 g/ml starts its replication and continues to be produced throughout the synthetic period.”
Claim · model-written summary
Both labeled DNA fractions localized mainly to the 1,000 × g sediment fraction.
Not reportedTaxon
Verbatim
e0“The labeled satellite DNA, as well as the labeled main band DNA, was localized mainly in the subcellular fraction of 1,000 × g sediments obtained from tissue homogenates.”
Claim · model-written summary
Triton X-100 did not modify the DNA localization patterns.
- Treatment
- addition of Triton X-100e0
- Outcome
- patterns of cellular localizatione0
- Direction
- not modifiede0
Not reportedTaxonComparator
Verbatim
e0“The patterns of cellular localization were not modified by the addition of Triton X-100 to the initial homogenates.”
Claim · model-written summary
A considerable fraction of labeled satellite DNA persisted in nuclease-resistant chromatin subunits.
Not reportedTaxon
Verbatim
e0“A considerable portion of the labeled satellite DNA was found in nuclease-resistant chromatin subunits after limited digestion of the isolated chromatin with micrococcal nuclease.”