| 10 matches found in 7 documents. Search time: 0.042 seconds. |
|---|
|
Score: 3.00 |
|---|
| Title: Phospholipid signaling responses in salt-stressed rice leaves .
| | Author: Darwish E Testerink C Khalil M El-Shihy O Munnik T | | Journal: Plant Cell Physiol Citation: V : 50 P : 986-97 Year: 2009 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19369274 Accession (PMID): 19369274 | | Abstract: Salinity is one of the major environmental factors limiting growth and productivity of rice plants .
In this study , the effect of salt stress on phospholipid signaling responses in rice leaves was investigated .
Leaf cuts were radiolabeled with 32P-orthophosphate and the lipids extracted and analyzed by thin-layer chromatography , autoradiography and phosphoimaging .
Phospholipids were identified by co-migration of known standards .
Results showed that 32P ( i ) was rapidly incorporated into the minor lipids , phosphatidylinositol bisphosphate ( PIP2 ) and phosphatidic acid ( PA ) and , interestingly , also into the structural lipids phosphatidylethanolamine ( PE ) and phosphatidylglycerol ( PG ) , which normally label relatively slowly , like phosphatidylcholine ( PC ) and phosphatidylinositol ( PI ) .
Only very small amounts of PIP2 were found .
However , in response to salt stress ( NaCl ) , PIP2 levels rapidly ( <30 min ) increased up to 4-fold , in a time and dose-dependent manner .
PA and its phosphorylated product , diacylglycerolpyrophosphate ( DGPP ) , also increased upon NaCl stress , while cardiolipin ( CL ) levels decreased .
All other phospholipid levels remained unchanged .
PA signaling can be generated via the combined action of phospholipase C ( PLC ) and diacylglycerol kinase ( DGK ) or directly via phospholipase D ( PLD ) .
The latter can be measured in vivo , using a transphosphatidylation assay .
Interestingly , these measurements revealed that salt stress inhibited PLD activity , indicating that the salt stress-induced PA response was not due to PLD activity .
Comparison of the 32P-lipid responses in salt-tolerant and salt-sensitive cultivars revealed no significant differences .
Together these results show that salt stress rapidly activates several lipid responses in rice leaves but that these responses do not explain the difference in salt tolerance between sensitive and tolerant cultivars .
| Matching Sentences:
[ Sen. 5, subscore: 1.00 ]: Results showed that 32P ( i ) was rapidly incorporated into the minor lipids , phosphatidylinositol bisphosphate ( PIP2 ) and phosphatidic acid ( PA ) and , interestingly , also into the structural lipids phosphatidylethanolamine ( PE ) and phosphatidylglycerol ( PG ) , which normally label relatively slowly , like phosphatidylcholine ( PC ) and phosphatidylinositol ( PI ) .
[ Sen. 6, subscore: 1.00 ]: Only very small amounts of PIP2 were found .
[ Sen. 7, subscore: 1.00 ]: However , in response to salt stress ( NaCl ) , PIP2 levels rapidly ( <30 min ) increased up to 4-fold , in a time and dose-dependent manner .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 2.00 |
|---|
| Title: Purification and Characterization of Membrane-Bound Inositol Phospholipid-Specific Phospholipase C from Suspension-Cultured Rice ( Oryza sativa L ) Cells ( Identification of a Regulatory Factor ) .
| | Author: Yotsushima K Mitsui T Takaoka T Hayakawa T Igaue I | | Journal: Citation: V : 102 ( 1 ) P : 165-172 Year: 1993 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12231806 Accession (PMID): 12231806 | | Abstract: A membrane-bound inositol phospholipid-specific phospholipase C was solubilized from rice ( Oryza sativa L ) microsomal membranes and purified to apparent homogeneity using a series of chromatographic separations .
The apparent molecular mass of the enzyme was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 42 , 000 D , and the isoelectric point was 5 . 1 .
The optimum pH for the enzyme activity was approximately 6 . 5 , and the enzyme was activated by both Ca2+ and Sr2+ .
The chemical and catalytic properties of the purified membrane-bound phospholipase C differed from those of the soluble enzyme reported previously ( K Yotsushima , K Nakamura , T Mitsui , I Igaue [ 1992 ] Biosci Biotech Biochem 56 : 1247-1251 ) .
In addition , we found a regulatory factor for the phosphatidylinositol-4 , 5-bisphosphate ( PIP2 ) hydrolyzing activity of phospholipase C from rice cells .
The regulatory factor was dissociated from the catalytic subunit of phospholipase C during the purification .
The regulatory factor was necessary to induce PIP2-hydrolyzing activity of both membrane-bound and -soluble phospholipase C ; these purified enzymes had no activity alone .
Because the plasma membranes isolated from rice cells could also act as a regulatory factor , the regulatory factor seems to be localized in the plasma membranes .
Regulation of inositol phospholipid turnover in rice cells is discussed . | Matching Sentences:
[ Sen. 5, subscore: 1.00 ]: In addition , we found a regulatory factor for the phosphatidylinositol-4 , 5-bisphosphate ( PIP2 ) hydrolyzing activity of phospholipase C from rice cells .
[ Sen. 7, subscore: 1.00 ]: The regulatory factor was necessary to induce PIP2-hydrolyzing activity of both membrane-bound and -soluble phospholipase C ; these purified enzymes had no activity alone .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
|---|
| Title: Expression of two PIP genes in rapidly growing internodes of rice is not primarily controlled by meristem activity or cell expansion .
| | Author: Malz S Sauter M | | Journal: Plant Mol . Biol . Citation: V : 40 ( 6 ) P : 985-95 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10527423 Accession (PMID): 10527423 | | Abstract: Membrane intrinsic proteins facilitate movement of small molecules often times functioning as water channels .
We have identified two genes from rice which encode proteins with characteristic features of plasma membrane intrinsic proteins ( PIP ) .
They possess six membrane-spanning domains , an NPA repeat , overall high sequence homologies and characteristic C and N-terminal hallmark motifs which allowed assignment of OsPIP1a to the PIP1 subfamily and of OsPIP2a to the PIP2 subfamily .
OsPIP1a and OsPIP2a showed similar but not identical expression patterns .
The two genes were expressed at higher levels in seedlings than in adult plants and expression in the primary root was regulated by light .
In internodes of deepwater rice plants which were induced to grow rapidly by submergence , transcript levels were slightly induced in the intercalary meristem ( IM ) and slightly reduced in the elongation zone ( EZ ) after 18 h .
In internodes of GA-induced excised stem sections transcript levels transiently declined in the IM and EZ after 1 h and subsequently recovered to elevated levels after 18 h .
GA also induced OsPIP expression in non-growing it issue after 18 h .
In the IM of submergence-induced stem sections transcript levels remained constitutive .
The different growth-promoting treatments showed no direct correlation between growth rate and OsPIP gene expression in dividing or expanding cells .
In fact , treatment of excised stem sections with ABA or drought stress induced similar changes in OsPIP expression in the growing zone during the first 6 h as GA did .
We conclude that regulation of OsPIP1a and OsPIP2a expression is not primarily controlled by growth .
GA-induced growth may however change the water status of cells which in turn results in altered PIP abundance . | Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: They possess six membrane-spanning domains , an NPA repeat , overall high sequence homologies and characteristic C and N-terminal hallmark motifs which allowed assignment of OsPIP1a to the PIP1 subfamily and of OsPIP2a to the PIP2 subfamily .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
|---|
| Title: Loss of a member of the aquaporin gene family , aqpA affects spore dormancy in Dictyostelium .
| | Author: Mitra BN Yoshino R Morio T Yokoyama M Maeda M Urushihara H Tanaka Y | | Journal: Gene Citation: V : 251 ( 2 ) P : 131-9 Year: 2000 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10876090 Accession (PMID): 10876090 | | Abstract: We isolated and characterized a gene from Dictyostelium discoideum , which encodes a protein of 279 amino acids ( 30 . 6kDa ) containing six transmembrane domains with two highly conserved motifs of asparagine-proline-alanine ( NPA ) found in the aquaporin family of water-channel proteins , although the second motif of the protein has been modified into NPV ( asparagine-proline-valine ) .
The deduced amino acid sequence of the gene , which we have named aqpA , is 39% identical to D discoideum WacA , 26% identical to human Aqp5 , 26% identical to Oryza sativa PIP2a , 25% identical to yeast Aqy1 and 24% identical to Ecoli AqpZ .
Southern analyses indicated that aqpA is present as a single copy in the genome .
Northern blot analysis showed that the developmentally regulated 1kb mRNA transcript first appears at the tight mound stage ( 12h ) , and is abundant in fingers ( 16h ) and late culminants ( 20h ) .
In-situ hybridization of slugs revealed that aqpA mRNA accumulated in cells of the prespore region but not in those of the prestalk region .
Disruption of aqpA by homologous recombination did not significantly affect growth or developmental morphogenesis .
Although mutant spores were viable , when assayed soon after encapsulation , they became permeable to propidium iodide and lost viability after a week on the top of a fruiting body .
Thus , AqpA is essential to maintain spore dormancy perhaps through the regulation of water flow . | Matching Sentences:
[ Sen. 2, subscore: 1.00 ]: The deduced amino acid sequence of the gene , which we have named aqpA , is 39% identical to D discoideum WacA , 26% identical to human Aqp5 , 26% identical to Oryza sativa PIP2a , 25% identical to yeast Aqy1 and 24% identical to Ecoli AqpZ .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
|---|
| Title: Effect of feeding protein deficient diet on phospholipid turnover and protein kinase C mediated protein phosphorylation in rat brain .
| | Author: Bansal SK Kathayat R Jaiswal AS Taneja KK Malhotra P Basir SF .
| | Journal: Indian J Exp . Biol . Citation: V : 38 ( 4 ) P : 323-31 Year: 2000 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11218807 Accession (PMID): 11218807 | | Abstract: Feeding of protein deficient diet is known to alter the transmembrane signalling in brain of rat by reducing total protein kinase C ( PKC ) activity .
Phospholipid metabolism regulates the activation of PKC through generation of second messengers and the extent of PKC activation accordingly influences the magnitude of phosphorylation of its endogenous substrate proteins .
Thus it was speculated that ingestion of protein deficient diet may modify the turnover rate of membrane phospholipids and magnitude of phosphorylation of endogenous substrate proteins of PKC .
The experiments were conducted on rats fed on three different types of laboratory prepared diets viz . casein ( 20% casein ) , deficient ( 4% protein , rice flour as source of protein ) and supplemented ( deficient diet supplemented with L-lysine and DL-threonine ) for 28 days .
The metabolism of phosphoinositides ( PIs ) and phosphatidyl choline ( PC ) was studied by equilibrium labeling with [ 3H ] myo inositol and [ 14C methyl ] choline chloride respectively .
The phosphorylation of endogenous substrate proteins of PKC was studied by using 32P-gamma-ATP followed by SDS-PAGE and autoradiography .
The results suggest that in deficient group , there is an increased incorporation of [ 3H ] myo inositol in PIs and inositol phosphate pool in comparison to the casein group .
The phosphatidyl inositol ( PI ) turnover reduced , although there was a marginal increase in the phosphatidyl inositol monophosphate ( PIP ) and phosphatidyl inositol bis phosphate ( PIP2 ) .
Supplementation of diet showed a reversal of the pattern towards control to a considerable extent .
In the deficient group , PC metabolism showed an increased incorporation of [ 14C methyl ] choline in choline phospholipids but decreased incorporation in phosphoryl choline in comparison with the casein group .
The increase in total PC contents was significant but marginal in residue contents .
The turnover rate of PC increased only marginally and that of residue declined .
Supplementation of diet reduced the total contents of PC and residue , but the turnover rate of PC and residue remained still higher .
Phosphorylation of endogenous proteins showed four different proteins of 78 , 46 , 33 and 16 kDa to be the substrates of PKC in casein group .
In deficient group , phosphorylation of these proteins increased markedly while supplementation of diet had a reversing effect rendering the values to be intermediate between casein and the supplemented group .
The changes in phospholipid metabolism and in phosphorylation of endogenous substrate proteins of PKC suggest that dietary protein deficiency causes alterations in transmembrane signalling mechanism in rat brain .
These effects are partially reversed by improving the quality of proteins in the diet .
| Matching Sentences:
[ Sen. 8, subscore: 1.00 ]: The phosphatidyl inositol ( PI ) turnover reduced , although there was a marginal increase in the phosphatidyl inositol monophosphate ( PIP ) and phosphatidyl inositol bis phosphate ( PIP2 ) .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
