Abstract
An analysis was undertaken of the effects of a toxic metal, zinc, on plant cell suspension cultures of the TBY–2 cell line of tobacco (Nicotiana tabacum cv. Bright Yellow 2) in order to determine whether Zn acts in a cell cycle-specific manner. In the control treatment (0 Zn), following a 24 h synchronization with aphidicolin and 7 h after the release from the inhibitor, the mitotic index peaked at 45%. The inclusion of Zn in the 24 h aphidicolin treatment (100, 200 or 300 μM Zn) resulted in a concentration–dependent decrease in the mitotic peak to 30%, 22% and 10%, respectively, but did not affect the timing of the peak. Hence, despite high concentrations of Zn, cells traversed from S–phase to mitosis, albeit in smaller proportions, at the same rate as the controls. Cells treated with 0, 100 or 200 μM Zn during synchronization and then released into Zn–free media showed successive peaks in mitotic index at 7 h and 21 h following release, i.e. Zn-treated cells progressed through a complete cell cycle at the same rate as the controls. Synchronization and subsequent release into Zn–containing medium (100 μM) examined the effect of the metal on predominantly late G1 cells. In this treatment, the mitotic index peaked at 7 h and 19 h, indicating a slightly faster cell cycle (12 h) compared with the control (14 h). Continuous exposure to 100 μM Zn through both synchronization and release resulted in a cell cycle of 11 h and a differential effect on the component phases: M–phase lengthened (1.5 h to 3.5 h) and G1 shortened (6 h to 1 h) compared with the control treatment. Vital staining (Evans Blue) revealed that cell mortality increased from 2.7% (0 Zn) to 6.1% and 6.5% at 100 and 200 μM Zn, respectively. The Zn content of cells increased 40–lfold from 0 to 100 μM Zn. The data are consistent with the effects of Zn reducing the cycling cell population primarily through cell arrest rather than cell death, but also reveal that a substantial population of TBY–2 cells progressed through the cell cycle despite accumulating Zn. In particular, the duration of G2 and S-phase was remarkably invariant, clearly indicating that once plant cells meet the requirements of late G1 check-points, they are committed to divide, even in the presence of toxic concentrations of Zn. The synchronous TBY–2 cell suspension, which lacks the heterogeneity and developmental constraints of plant meristems, is an excellent system to study the effects of known toxic metals, and indeed other environmental factors, on the plant cell cycle.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 15
Claim · model-written summary
Zinc reduced the mitotic peak dose dependently to 30%, 22%, and 10%.
- Taxon
- tobacco
Nicotiana tabacumt0 - Treatment
- 100, 200 or 300 μM Zne0
- Outcome
- mitotic peake0
- Direction
- decreasee0
- Value
- 30%, 22% and 10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The inclusion of Zn in the 24 h aphidicolin treatment (100, 200 or 300 μM Zn) resulted in a concentration–dependent decrease in the mitotic peak to 30%, 22% and 10%, respectively”
t0“tobacco cell suspension”
Claim · model-written summary
Zinc did not change timing of the mitotic peak.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Zne1
- Outcome
- timing of the peake0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but did not affect the timing of the peak.”
t0“tobacco cell suspension”
e1“The inclusion of Zn in the 24 h aphidicolin treatment (100, 200 or 300 μM Zn) resulted in a concentration–dependent decrease in the mitotic peak to 30%, 22% and 10%, respectively”
Claim · model-written summary
Cells released into zinc free medium completed a cell cycle at the control rate.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Zn-treated cellse0
- Outcome
- complete cell cyclee0
- Direction
- same ratee0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Zn-treated cells progressed through a complete cell cycle at the same rate as the controls.”
t0“tobacco cell suspension”
Claim · model-written summary
Zinc during release slightly accelerated the cell cycle to 12 h versus 14 h.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Zne1
- Outcome
- cell cyclee0
- Direction
- fastere0
- Value
- 12 he0
- Qualifier
- 14 he0
- Comparator
- controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“indicating a slightly faster cell cycle (12 h) compared with the control (14 h).”
t0“tobacco cell suspension”
e1“The inclusion of Zn in the 24 h aphidicolin treatment (100, 200 or 300 μM Zn) resulted in a concentration–dependent decrease in the mitotic peak to 30%, 22% and 10%, respectively”
Claim · model-written summary
Continuous zinc exposure shortened the cell cycle to 11 h.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- 100 μM Zne0
- Outcome
- cell cyclee0
- Value
- 11 he0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Continuous exposure to 100 μM Zn through both synchronization and release resulted in a cell cycle of 11 h”
t0“tobacco cell suspension”
Claim · model-written summary
Continuous zinc exposure lengthened M phase from 1.5 h to 3.5 h.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Zne1
- Outcome
- M–phasee0
- Direction
- lengthenede0
- Value
- 3.5 he0
- Comparator
- 1.5 he0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“M–phase lengthened (1.5 h to 3.5 h)”
t0“tobacco cell suspension”
e1“The inclusion of Zn in the 24 h aphidicolin treatment (100, 200 or 300 μM Zn) resulted in a concentration–dependent decrease in the mitotic peak to 30%, 22% and 10%, respectively”
Claim · model-written summary
Continuous zinc exposure shortened G1 from 6 h to 1 h.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Zne1
- Outcome
- G1e0
- Direction
- shortenede0
- Value
- 1 he0
- Qualifier
- 6 he0
- Comparator
- control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“G1 shortened (6 h to 1 h) compared with the control treatment.”
t0“tobacco cell suspension”
e1“The inclusion of Zn in the 24 h aphidicolin treatment (100, 200 or 300 μM Zn) resulted in a concentration–dependent decrease in the mitotic peak to 30%, 22% and 10%, respectively”
Claim · model-written summary
Mortality increased from 2.7% without zinc to 6.1% at 100 μM.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- 100e0
- Outcome
- cell mortalitye0
- Direction
- increasede0
- Value
- 6.1%e0
- Qualifier
- 2.7%e0
- Comparator
- 0 Zne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cell mortality increased from 2.7% (0 Zn) to 6.1% and 6.5% at 100 and 200 μM Zn, respectively.”
t0“tobacco cell suspension”
Claim · model-written summary
Mortality increased from 2.7% without zinc to 6.5% at 200 μM.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- 200 μM Zne0
- Outcome
- cell mortalitye0
- Direction
- increasede0
- Value
- 6.5%e0
- Qualifier
- 2.7%e0
- Comparator
- 0 Zne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cell mortality increased from 2.7% (0 Zn) to 6.1% and 6.5% at 100 and 200 μM Zn, respectively.”
t0“tobacco cell suspension”
Claim · model-written summary
Cell zinc content rose 40 fold from 0 to 100 μM.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- 100 μM Zne0
- Outcome
- Zn content of cellse0
- Direction
- increasede0
- Value
- 40–lfolde0
- Comparator
- 0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Zn content of cells increased 40–lfold from 0 to 100 μM Zn.”
t0“tobacco cell suspension”
Claim · model-written summary
The authors inferred zinc reduces cycling primarily through arrest rather than death.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Zne0
- Outcome
- cycling cell populatione0
- Direction
- reducinge0
- Qualifier
- cell arrest rather than cell deathe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The data are consistent with the effects of Zn reducing the cycling cell population primarily through cell arrest rather than cell death”
t0“tobacco cell suspension”
Claim · model-written summary
Substantial tobacco cell population progressed through the cycle despite zinc accumulation.
- Taxon
- tobaccoNicotiana tabacumt0
- Material
- TBY–2e0
- Outcome
- progressed through the cell cyclee0
- Qualifier
- despite accumulating Zne0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a substantial population of TBY–2 cells progressed through the cell cycle despite accumulating Zn.”
t0“tobacco cell suspension”
Claim · model-written summary
G2 and S phase duration was invariant under zinc exposure.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Zne1
- Outcome
- duration of G2 and S-phasee0
- Direction
- invariante0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the duration of G2 and S-phase was remarkably invariant”
t0“tobacco cell suspension”
e1“The inclusion of Zn in the 24 h aphidicolin treatment (100, 200 or 300 μM Zn) resulted in a concentration–dependent decrease in the mitotic peak to 30%, 22% and 10%, respectively”
Claim · model-written summary
The authors interpret late G1 passage as commitment to divide despite toxic zinc.
- Taxon
- tobaccoNicotiana tabacumt0
- Organ / stage
- late G1 check-pointse0
- Outcome
- committed to dividee0
- Qualifier
- even in the presence of toxic concentrations of Zne0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“once plant cells meet the requirements of late G1 check-points, they are committed to divide, even in the presence of toxic concentrations of Zn.”
t0“tobacco cell suspension”
Claim · model-written summary
The synchronous tobacco suspension is proposed as a useful system for studying toxic metal effects on cell cycle.
- Taxon
- tobaccoNicotiana tabacumt0
- Material
- TBY–2e0
- Outcome
- excellent system to study the effects of known toxic metalse0
- Comparator
- plant meristemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The synchronous TBY–2 cell suspension, which lacks the heterogeneity and developmental constraints of plant meristems, is an excellent system to study the effects of known toxic metals, and indeed other environmental factors, on the plant cell cycle.”
t0“tobacco cell suspension”
The same questions in other papers
zinc atom · pest · Nicotiana tabacum (tobacco)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- negative
zinc atom · nutrient: content · Nicotiana tabacum (tobacco)Positive and negative results
1 paper in the same direction as this paper · 3 in the opposite direction
- positive
- positive
- positive
1 paper more in this group
See all 5 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.