Abstract
Diacylglycerol contents of excised soybean (Glycine max L.) hypocotyl segments, incubated for 4 hours in the presence or absence of a growth promoting concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) were monitored by three different methods as a sensitive measure of the action in vivo of C-type phospholipases. By all three methods, steady state levels of diacylglycerols representing about 3% of the total lipids or about 7% of the neutral lipids, depending on method of assay, declined 18% over 4 hours of incubation as determined by extraction of total lipids and analysis by thin layer chromatography and densitometry. The average decline with 2,4-D-treated segments was less but the difference from controls was not significant. In those experiments where a small effect of 2,4-D was noted, the fraction showing an elevated diacylglycerol level in response to 2,4-D, after separation into membrane and supernatant fractions, was the supernatant and not the membranes. Results were confirmed from analyses of total fatty acids in each of the major lipid fractions and from diacylglycerol assays by conversion into phosphatidic acid upon incubation with [gamma-(32)P]ATP and purified diacylglycerol phosphokinase from Escherichia coli. In the presence of 2,4-D, the diacylglycerol content of the membranes was unchanged compared to membranes from control segments. As with the densitometric method, the small 2,4-D induced increase in diacylglycerols, when observed, was insignificant and in the supernatant. The only membrane-associated lipid fraction consistently showing a response to 2,4-D was the fraction containing sterols esterified with fatty acids. Either total microsomes or purified plasma membranes when incubated for 10 to 20 minutes with 1 micromolar 2,4-D showed no accelerated formation of diacylglycerols compared to membranes not incubated. The results do not support operation during auxin growth of the animal paradigm where diacylglycerol activation of C-type protein kinases occurs in response to activated phospholipase C breakdown of phosphoinositides.
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Claims 11
Claim · model-written summary
Diacylglycerols represented about 3% of total lipids.
- Taxon
- soybean
Glycine maxe1 - Organ / stage
- hypocotyl segmentse1
- Outcome
- diacylglycerolse0
- Value
- about 3%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“diacylglycerols representing about 3% of the total lipids or about 7% of the neutral lipids”
e1“soybean (Glycine max L.) hypocotyl segments”
Claim · model-written summary
Diacylglycerols represented about 7% of neutral lipids.
- Taxon
- soybeanGlycine maxe1
- Organ / stage
- hypocotyl segmentse1
- Outcome
- diacylglycerolse0
- Value
- about 7%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“diacylglycerols representing about 3% of the total lipids or about 7% of the neutral lipids”
e1“soybean (Glycine max L.) hypocotyl segments”
Claim · model-written summary
Diacylglycerol levels declined 18% during four hours of incubation.
- Taxon
- soybeanGlycine maxe1
- Outcome
- steady state levels of diacylglycerolse2
- Direction
- declinede0
- Value
- 18%e0
- Qualifier
- over 4 hours of incubatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“declined 18% over 4 hours of incubation”
e1“soybean (Glycine max L.) hypocotyl segments”
e2“steady state levels of diacylglycerols”
Claim · model-written summary
The smaller average decline under 2,4-D did not differ significantly from controls.
- Taxon
- soybeanGlycine maxe1
- Treatment
- 2,4-D-treatede0
- Outcome
- steady state levels of diacylglycerolse2
- Direction
- lesse0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average decline with 2,4-D-treated segments was less but the difference from controls was not significant.”
e1“soybean (Glycine max L.) hypocotyl segments”
e2“steady state levels of diacylglycerols”
Claim · model-written summary
When a small 2,4-D response appeared, elevated diacylglycerol was in supernatant rather than membranes.
- Taxon
- soybeanGlycine maxe1
- Treatment
- 2,4-De0
- Outcome
- diacylglycerol levele0
- Direction
- elevatede0
- Qualifier
- supernatante0
- Comparator
- membranese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the fraction showing an elevated diacylglycerol level in response to 2,4-D, after separation into membrane and supernatant fractions, was the supernatant and not the membranes”
e1“soybean (Glycine max L.) hypocotyl segments”
Claim · model-written summary
Membrane diacylglycerol content was unchanged with 2,4-D compared with control membranes.
- Taxon
- soybeanGlycine maxe1
- Treatment
- 2,4-De0
- Outcome
- diacylglycerol content of the membranese0
- Direction
- unchangede0
- Comparator
- membranes from control segmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the presence of 2,4-D, the diacylglycerol content of the membranes was unchanged compared to membranes from control segments.”
e1“soybean (Glycine max L.) hypocotyl segments”
Claim · model-written summary
The small 2,4-D induced diacylglycerol increase in supernatant was insignificant when seen.
- Taxon
- soybeanGlycine maxe1
- Treatment
- 2,4-De0
- Outcome
- diacylglycerolse0
- Direction
- increasee0
- Qualifier
- supernatante0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the small 2,4-D induced increase in diacylglycerols, when observed, was insignificant and in the supernatant”
e1“soybean (Glycine max L.) hypocotyl segments”
Claim · model-written summary
The membrane lipid fraction containing fatty-acid-esterified sterols consistently responded to 2,4-D.
- Taxon
- soybeanGlycine maxe1
- Treatment
- 2,4-De0
- Outcome
- fraction containing sterols esterified with fatty acidse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The only membrane-associated lipid fraction consistently showing a response to 2,4-D was the fraction containing sterols esterified with fatty acids.”
e1“soybean (Glycine max L.) hypocotyl segments”
Claim · model-written summary
Microsomes incubated with 1 micromolar 2,4-D showed no accelerated diacylglycerol formation.
- Taxon
- soybeanGlycine maxe1
- Material
- total microsomese0
- Treatment
- 1 micromolar 2,4-De0
- Outcome
- formation of diacylglycerolse0
- Direction
- no acceleratede0
- Comparator
- membranes not incubatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Either total microsomes or purified plasma membranes when incubated for 10 to 20 minutes with 1 micromolar 2,4-D showed no accelerated formation of diacylglycerols compared to membranes not incubated.”
e1“soybean (Glycine max L.) hypocotyl segments”
Claim · model-written summary
Purified plasma membranes incubated with 1 micromolar 2,4-D showed no accelerated diacylglycerol formation.
- Taxon
- soybeanGlycine maxe1
- Treatment
- 1 micromolar 2,4-De0
- Outcome
- formation of diacylglycerolse0
- Direction
- no acceleratede0
- Qualifier
- purified plasma membranese0
- Comparator
- membranes not incubatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Either total microsomes or purified plasma membranes when incubated for 10 to 20 minutes with 1 micromolar 2,4-D showed no accelerated formation of diacylglycerols compared to membranes not incubated.”
e1“soybean (Glycine max L.) hypocotyl segments”
Claim · model-written summary
The results did not support diacylglycerol activation of C-type protein kinases during auxin growth.
- Taxon
- soybeanGlycine maxe1
- Outcome
- diacylglycerol activation of C-type protein kinasese0
- Qualifier
- during auxin growthe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The results do not support operation during auxin growth of the animal paradigm where diacylglycerol activation of C-type protein kinases occurs in response to activated phospholipase C breakdown of phosphoinositides.”
e1“soybean (Glycine max L.) hypocotyl segments”
The same questions in other papers
2,4-D · molecular: metabolites · Glycine max (soybean)Positive and negative results
1 paper in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- positive
2 papers more in this group
See all 6 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.