Abstract
Influence of growth temperature on the capacity of the mitochondrial alternative pathway of electron transport was investigated using etiolated corn (Zea mays L.) seedlings. These seedlings were grown to comparable size in either a warm (30 degrees C) or a cold (13 degrees C) temperature regime, and then their respiration rates were measured as O(2) uptake at 25 degrees C. The capacity of the alternative pathway (KCN-insensitive O(2) uptake) was found essentially to double in shoots of cold-grown seedlings. This increased capacity slowly developed over several days growth in the cold, but was lost within 1 day when the seedlings were exposed to a warm regime. When mitochondria were isolated from the shoots of these seedlings, a greater potential for flow through the alternative path was observed in mitochondria from the cold-grown seedlings with all substrates used (an average increase of 84%). Using exogenous NADH as the substrate, the effect of the electrochemical gradient on measurable capacities of the cytochrome and alternative pathways was investigated in mitochondria from both etiolated seedlings and thermogenic spadices. The uncoupler FCCP (p-trifluoromethoxycarbonylcyanide phenylhydrazone) was used to diminish the electrochemical gradient when desired. In corn (Zea mays L.) shoot and mung bean (Vigna radiata L.) hypocotyl mitochondria, which have relatively low capacities of the alternative pathway, increased flow through the cytochrome chain in the absence of the electrochemical gradient was found not to influence the potential for flow through the alternative path. However, in mitochondria from skunk cabbage (Symplocarpus foetidus L.) and voodoo lily (Sauromatum guttatum Schott) spadices, which have high capacities of the alternative pathway, increased flow through the cytochrome chain in the absence of the gradient occurred at the expense of flow through the alternative pathway. These results suggest that in mitochondria of thermogenic spadices, the combined capacities of the cytochrome and alternative paths exceed the capacity of the exogenous NADH dehydrogenase. The effect of assay pH on measurable capacities of the cytochrome and alternative paths was determined over a pH range of 5.6 to 8.8 using exogenous NADH as the mitochondrial substrate. When the electrochemical gradient was present, it limited the electron transport rate and little effect of assay pH was observed. However, when formation of the gradient was prevented through inclusion of FCCP, measurable capacities of the cytochrome and alternative paths were found to be greatly influenced by pH. This experiment also revealed that the potential for respiratory control is largely dependent upon the assay pH.
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 11
Claim · model-written summary
Cold-grown corn shoots had essentially double the alternative pathway capacity.
- Taxon
- corn
Zea mays subsp. mayse1 - Organ / stage
- shootse2
- Treatment
- cold-grown seedlingse2
- Outcome
- capacity of the alternative pathway (KCN-insensitive O(2) uptake)e2
- Direction
- doublee2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shoots of cold-grown seedlings”
e1“etiolated corn (Zea mays L.) seedlings”
e2“The capacity of the alternative pathway (KCN-insensitive O(2) uptake) was found essentially to double in shoots of cold-grown seedlings”
Claim · model-written summary
The increased cold-grown corn respiratory capacity developed over several days and was lost within one warm day.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- increased capacitye1
- Qualifier
- lost within 1 daye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“etiolated corn (Zea mays L.) seedlings”
e1“This increased capacity slowly developed over several days growth in the cold, but was lost within 1 day when the seedlings were exposed to a warm regime”
Claim · model-written summary
Mitochondria from cold-grown corn shoots had an 84% average increase in potential alternative pathway flow.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- cold-grown seedlingse1
- Outcome
- potential for flow through the alternative pathe1
- Direction
- greatere1
- Value
- 84%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“etiolated corn (Zea mays L.) seedlings”
e1“a greater potential for flow through the alternative path was observed in mitochondria from the cold-grown seedlings with all substrates used (an average increase of 84%)”
Claim · model-written summary
In corn shoot mitochondria, increased cytochrome flow without the gradient did not influence potential alternative pathway flow.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- shoote0
- Outcome
- potential for flow through the alternative pathe0
- Direction
- not to influencee0
- Qualifier
- in the absence of the electrochemical gradiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In corn (Zea mays L.) shoot and mung bean (Vigna radiata L.) hypocotyl mitochondria, which have relatively low capacities of the alternative pathway, increased flow through the cytochrome chain in the absence of the electrochemical gradient was found not to influence the potential for flow through the alternative path”
Claim · model-written summary
In mung bean hypocotyl mitochondria, increased cytochrome flow without the gradient did not influence potential alternative pathway flow.
- Taxon
- mung bean
.jpg?width=60)
Vigna radiatae0 - Organ / stage
- hypocotyle0
- Outcome
- potential for flow through the alternative pathe0
- Direction
- not to influencee0
- Qualifier
- in the absence of the electrochemical gradiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“In corn (Zea mays L.) shoot and mung bean (Vigna radiata L.) hypocotyl mitochondria, which have relatively low capacities of the alternative pathway, increased flow through the cytochrome chain in the absence of the electrochemical gradient was found not to influence the potential for flow through the alternative path”
Claim · model-written summary
In skunk cabbage spadices, increased cytochrome flow without the gradient came at the expense of alternative pathway flow.
- Taxon
- skunk cabbage
Symplocarpus foetiduse0 - Organ / stage
- spadicese0
- Outcome
- flow through the alternative pathwaye0
- Direction
- at the expense ofe0
- Qualifier
- in the absence of the gradiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in mitochondria from skunk cabbage (Symplocarpus foetidus L.) and voodoo lily (Sauromatum guttatum Schott) spadices, which have high capacities of the alternative pathway, increased flow through the cytochrome chain in the absence of the gradient occurred at the expense of flow through the alternative pathway”
Claim · model-written summary
In voodoo lily spadices, increased cytochrome flow without the gradient came at the expense of alternative pathway flow.
- Taxon
- voodoo lily
.jpg?width=60)
Sauromatum venosume0 - Organ / stage
- spadicese0
- Outcome
- flow through the alternative pathwaye0
- Direction
- at the expense ofe0
- Qualifier
- in the absence of the gradiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“in mitochondria from skunk cabbage (Symplocarpus foetidus L.) and voodoo lily (Sauromatum guttatum Schott) spadices, which have high capacities of the alternative pathway, increased flow through the cytochrome chain in the absence of the gradient occurred at the expense of flow through the alternative pathway”
Claim · model-written summary
The combined cytochrome and alternative capacities may exceed exogenous NADH dehydrogenase capacity in thermogenic spadices.
- Organ / stage
- thermogenic spadicese0
- Gene
- exogenous NADH dehydrogenasee0
- Outcome
- combined capacities of the cytochrome and alternative paths exceed the capacity of the exogenous NADH dehydrogenasee0
Not reportedTaxon
Verbatim
e0“These results suggest that in mitochondria of thermogenic spadices, the combined capacities of the cytochrome and alternative paths exceed the capacity of the exogenous NADH dehydrogenase”
t0“Plant Mitochondria”
Claim · model-written summary
With the gradient present, electron transport was limited and assay pH had little effect.
Not reportedTaxonComparator
Verbatim
e0“When the electrochemical gradient was present, it limited the electron transport rate and little effect of assay pH was observed”
t0“Plant Mitochondria”
Claim · model-written summary
With FCCP preventing the gradient, pH greatly influenced measurable cytochrome and alternative capacities.
- Treatment
- inclusion of FCCPe0
- Outcome
- measurable capacities of the cytochrome and alternative pathse0
- Qualifier
- greatly influenced by pHe0
Not reportedTaxonDirection
Verbatim
e0“when formation of the gradient was prevented through inclusion of FCCP, measurable capacities of the cytochrome and alternative paths were found to be greatly influenced by pH”
t0“Plant Mitochondria”
Claim · model-written summary
Potential respiratory control depended largely on assay pH.
Not reportedTaxonDirection
Verbatim
e0“the potential for respiratory control is largely dependent upon the assay pH”
t0“Plant Mitochondria”
The same questions in other papers
cold · nutrient: content · Zea mays (maize)Positive and negative results
9 in the opposite direction
- negative
- negative
- negative
6 papers more in this group
See all 10 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.