Abstract
The oxidation of exogenous NADH by mitochondria from potato ( Solanum tuberosum L., cv. Bintje) tubers, measured with different electron acceptors, oxygen, cytochrome c , duroquinone and ubiquinone 1, was greatly enhanced under high salt conditions compared to low salt conditions, confirming the stimulatory effect of electrostatic screeening of negative membrane charges by cations. In addition to this nonspecific stimulation, the oxidation of exogenous NADH showed a specific dependence on Ca 2+ . Results presented here suggest that calmodulin was not directly involved in the regulation of exogenous NADH oxidation by potato mitochondria: (1) Calmodulin antagonists were found to inhibit electron flow at several sites in a nonspecific manner. (2) Using a phenothiazine‐Affi Gel column, it was not possible to demonstrate the presence of calmodulin in Triton X‐100 solubilized mitochondria. (3) Fractions eluted from a calmodulin‐Sepharose column with EGTA [ethyleneglycolbis (β‐aminoethylether)‐N, N, N′, N′‐tetraacetic acid] did not display any activity related to mitochondrial electron transport, suggesting that NADH dehydrogenase had no specific affinity for calmodulin. The possible indirect involvement of calmodulin in the regulation of exogenous NADH oxidation by Ca 2+ is discussed.
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Claims 7
Claim · model-written summary
High salt greatly enhanced exogenous NADH oxidation relative to low salt.
- Taxon
- potato
Solanum tuberosume0 - Material
- Bintjee0
- Organ / stage
- tuberse0
- Treatment
- high salt conditionse0
- Outcome
- oxidation of exogenous NADHe0
- Direction
- greatly enhancede0
- Comparator
- low salt conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The oxidation of exogenous NADH by mitochondria from potato ( Solanum tuberosum L., cv. Bintje) tubers, measured with different electron acceptors, oxygen, cytochrome c , duroquinone and ubiquinone 1, was greatly enhanced under high salt conditions compared to low salt conditions”
Claim · model-written summary
Exogenous NADH oxidation depended specifically on calcium.
- Taxon
- potatoSolanum tuberosume1
- Compound
- Ca 2+e0
- Outcome
- oxidation of exogenous NADHe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the oxidation of exogenous NADH showed a specific dependence on Ca 2+”
e1“mitochondria from potato ( Solanum tuberosum L., cv. Bintje) tubers”
Claim · model-written summary
Calmodulin antagonists inhibited electron flow nonspecifically at several sites.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- Calmodulin antagonistse0
- Outcome
- electron flowe0
- Direction
- inhibite0
- Qualifier
- at several sites in a nonspecific mannere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Calmodulin antagonists were found to inhibit electron flow at several sites in a nonspecific manner”
e1“mitochondria from potato ( Solanum tuberosum L., cv. Bintje) tubers”
Claim · model-written summary
Calmodulin was not detected in solubilized mitochondria using the affinity column.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- phenothiazine‐Affi Gel columne0
- Outcome
- presence of calmoduline0
- Qualifier
- Triton X‐100 solubilized mitochondriae0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Using a phenothiazine‐Affi Gel column, it was not possible to demonstrate the presence of calmodulin in Triton X‐100 solubilized mitochondria”
e1“mitochondria from potato ( Solanum tuberosum L., cv. Bintje) tubers”
Claim · model-written summary
EGTA-eluted fractions showed no mitochondrial electron transport activity.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- EGTAe0
- Gene
- calmoduline0
- Outcome
- activity related to mitochondrial electron transporte0
- Direction
- did not displaye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fractions eluted from a calmodulin‐Sepharose column with EGTA [ethyleneglycolbis (β‐aminoethylether)‐N, N, N′, N′‐tetraacetic acid] did not display any activity related to mitochondrial electron transport”
e1“mitochondria from potato ( Solanum tuberosum L., cv. Bintje) tubers”
Claim · model-written summary
The results suggest calmodulin does not directly regulate exogenous NADH oxidation.
- Taxon
- potatoSolanum tuberosume0
- Gene
- calmoduline0
- Outcome
- regulation of exogenous NADH oxidatione0
- Direction
- not directly involvede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results presented here suggest that calmodulin was not directly involved in the regulation of exogenous NADH oxidation by potato mitochondria”
Claim · model-written summary
The authors infer that NADH dehydrogenase lacks specific affinity for calmodulin.
- Taxon
- potatoSolanum tuberosume1
- Gene
- NADH dehydrogenasee0
- Outcome
- specific affinity for calmoduline0
- Direction
- no specific affinitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“suggesting that NADH dehydrogenase had no specific affinity for calmodulin”
e1“mitochondria from potato ( Solanum tuberosum L., cv. Bintje) tubers”
The same questions in other papers
salinity · molecular: metabolites · Solanum tuberosum (potato)Positive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- positive
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.