Abstract
Nitrate reductase activity was induced by nitrate in green corn (Zea mays) leaves in either light or darkness. The induction process required oxygen in darkness but not in light. A light treatment was required before the enzyme could be induced in etiolated leaves.The capacity for nitrate reductase induction by nitrate was positively correlated with the level of cytoplasmic polyribosomes under a variety of experimental conditions. (a) Light-grown leaves contained high levels of polyribosomes (84% of the total population, most of which were of the 80 S type); similarly high levels of nitrate reductase activity were induced. (b) The level of polyribosomes and the ability to form nitrate reductase activity rapidly decreased in light-grown leaves following transfer to an anaerobic environment in the dark; both parameters were maintained at a high level when light-grown leaves were kept in the light under anaerobic conditions. (c) The ability of light-grown leaves, previously placed in darkness under nitrogen to dissociate polyribosomes to monoribosomes, to form nitrate reductase activity again correlated with the level of reformed polyribosomes following transfer of the leaves back to light. (d) Etiolated leaves contained a low level of cytoplasmic polyribosomes (27%), and nitrate reductase activity was induced following exposure to light only after a lag of 2 to 4 hours. During this lag period there was a marked increase in the level of polyribosomes.The ability of leaves to form nitrate reductase activity and the level of polyribosomes also correlated with the level of in vitro incorporation of amino acids into protein by the isolated ribosome preparations. Thus, the apparent requirement of light for nitrate reductase induction in etiolated leaves seems not to be specific. Rather an influence of light upon the development of an active protein-synthesizing apparatus as evidenced by the state of polyribosomes is indicated.The results also show that energy from photosynthetic phosphorylation can be used to maintain cytoplasmic polyribosomes (and thus to drive cytoplasmic protein synthesis), at least under anaerobic conditions.
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Claims 13
Claim · model-written summary
Nitrate induced nitrate reductase activity in green corn leaves in light and darkness.
- Taxon
- corn
Zea mays subsp. mayse0 - Organ / stage
- leavese0
- Treatment
- nitratee0
- Gene
- Nitrate reductasee0
- Outcome
- Nitrate reductase activitye0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrate reductase activity was induced by nitrate in green corn (Zea mays) leaves in either light or darkness.”
Claim · model-written summary
Nitrate reductase induction required oxygen in darkness but not in light.
- Taxon
- CornZea mays subsp. mayst0
- Outcome
- induction process required oxygen in darkness but not in lighte0
- Qualifier
- in darkness but not in lighte0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The induction process required oxygen in darkness but not in light.”
t0“Corn Leaves”
Claim · model-written summary
Etiolated corn leaves required light before enzyme induction.
- Taxon
- CornZea mays subsp. mayst0
- Organ / stage
- etiolated leavese0
- Treatment
- light treatmente0
- Outcome
- enzyme could be inducede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A light treatment was required before the enzyme could be induced in etiolated leaves.”
t0“Corn Leaves”
Claim · model-written summary
Nitrate reductase induction capacity correlated positively with cytoplasmic polyribosome levels.
- Taxon
- CornZea mays subsp. mayst0
- Organ / stage
- cytoplasmic polyribosomese0
- Outcome
- capacity for nitrate reductase inductione0
- Direction
- positively correlatede0
- Qualifier
- under a variety of experimental conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The capacity for nitrate reductase induction by nitrate was positively correlated with the level of cytoplasmic polyribosomes under a variety of experimental conditions.”
t0“Corn Leaves”
Claim · model-written summary
Light-grown leaves had 84% polyribosomes and high induced nitrate reductase activity.
- Taxon
- CornZea mays subsp. mayst0
- Organ / stage
- Light-grown leavese0
- Outcome
- levels of polyribosomese0
- Direction
- highe0
- Value
- 84%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light-grown leaves contained high levels of polyribosomes (84% of the total population, most of which were of the 80 S type); similarly high levels of nitrate reductase activity were induced.”
t0“Corn Leaves”
Claim · model-written summary
Dark anaerobic transfer rapidly decreased polyribosomes and nitrate reductase formation ability in light-grown leaves.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- transfer to an anaerobic environment in the darke0
- Outcome
- level of polyribosomes and the ability to form nitrate reductase activitye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The level of polyribosomes and the ability to form nitrate reductase activity rapidly decreased in light-grown leaves following transfer to an anaerobic environment in the dark;”
t0“Corn Leaves”
Claim · model-written summary
Under anaerobic conditions, light maintained high polyribosome and nitrate reductase formation levels.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- kept in the light under anaerobic conditionse0
- Outcome
- both parameterse0
- Direction
- maintained at a high levele0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both parameters were maintained at a high level when light-grown leaves were kept in the light under anaerobic conditions.”
t0“Corn Leaves”
Claim · model-written summary
After dark nitrogen exposure, nitrate reductase formation again correlated with reformed polyribosome levels following return to light.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- transfer of the leaves back to lighte0
- Outcome
- to form nitrate reductase activitye0
- Direction
- correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“to form nitrate reductase activity again correlated with the level of reformed polyribosomes following transfer of the leaves back to light.”
t0“Corn Leaves”
Claim · model-written summary
Etiolated leaves had 27% cytoplasmic polyribosomes.
- Taxon
- CornZea mays subsp. mayst0
- Organ / stage
- Etiolated leavese0
- Outcome
- level of cytoplasmic polyribosomese0
- Direction
- lowe0
- Value
- 27%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Etiolated leaves contained a low level of cytoplasmic polyribosomes (27%),”
t0“Corn Leaves”
Claim · model-written summary
After light exposure, nitrate reductase induction in etiolated leaves had a 2 to 4 hour lag.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- exposure to lighte0
- Outcome
- nitrate reductase activity was inducede0
- Value
- 2 to 4 hourse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrate reductase activity was induced following exposure to light only after a lag of 2 to 4 hours.”
t0“Corn Leaves”
Claim · model-written summary
Polyribosome levels markedly increased during the induction lag.
- Taxon
- CornZea mays subsp. mayst0
- Outcome
- level of polyribosomese0
- Direction
- marked increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During this lag period there was a marked increase in the level of polyribosomes.”
t0“Corn Leaves”
Claim · model-written summary
Nitrate reductase formation ability and polyribosome levels correlated with in vitro amino acid incorporation into protein.
- Taxon
- CornZea mays subsp. mayst0
- Organ / stage
- isolated ribosome preparationse0
- Outcome
- ability of leaves to form nitrate reductase activity and the level of polyribosomese0
- Direction
- correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ability of leaves to form nitrate reductase activity and the level of polyribosomes also correlated with the level of in vitro incorporation of amino acids into protein by the isolated ribosome preparations.”
t0“Corn Leaves”
Claim · model-written summary
Photosynthetic phosphorylation can maintain cytoplasmic polyribosomes under anaerobic conditions.
- Taxon
- CornZea mays subsp. mayst0
- Outcome
- maintain cytoplasmic polyribosomese0
- Direction
- maintaine0
- Qualifier
- at least under anaerobic conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“energy from photosynthetic phosphorylation can be used to maintain cytoplasmic polyribosomes (and thus to drive cytoplasmic protein synthesis), at least under anaerobic conditions.”
t0“Corn Leaves”
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See all 34 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.