Abscisic Acid Suppresses the Hypersensitive Necrosis of Potato Tubers and Reverses the Arachidonic Acid-Induced Inhibition of Plasma Membrane-Bound ATPase

1991 ◽  
Vol 132 (2) ◽  
pp. 146-152 ◽  
Author(s):  
T. Érsek ◽  
E. P. Ladyzhenskaya ◽  
N. P. Korableva ◽  
A. Ádám
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Abscisic Acid ◽  
Potato Tubers ◽  
Membrane Bound

Possible Pathways Of Arachidonic Acid Liberation As Studied With Purified Phospholipases

1981 ◽  
Author(s):  
H Chap ◽  
B Perret ◽  
G Mauco ◽  
M Plantavid ◽  
F Laffont ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Phospholipase C ◽  
Ph Dependence ◽  
Plasma Lipoproteins ◽  
Heterogeneous Distribution ◽  
Outer Leaflet ◽  
Membrane Bound

Two kinds of informations about arachidonic acid (AA) metabolism in platelet phospholipids (PL) have been obtained from the use of purified phospholipases: 1) Beside the determination of PL sidedness in the plasma membrane, non-lytic degradation by phospholipase A2 + sphingomyelinase C showed that only 6 % of the total platelet AA is localized in the outer surface of the plasma membrane. This heterogeneous distribution is actually a consequence of PL asymmetry, since sphingomyelin and phosphatidylcholine, which predominate in membrane outer leaflet, contain only traces or relatively lower amounts, respectively, of AA than the internal lipids. It is further shown that incubating platelets with free AA specifically labels the large internal pool of AA, whereas the small external pool is renewed by a direct exchange of phosphatidylcholine with plasma lipoproteins. This offers a doublelabelling method allowing to explore the exact role of each AA pool.2) Platelet aggregation by Clostridium welchii phospholipase C produces the same metabolic changes (accumulation of phosphatidic and lysophosphatidic acids) as those induced by thrombin. These observations have led to describe the existence of a cytosolic phosphatidylinositol-specific phospholipase C and a membrane-bound diglyceride lipase. Both enzymes, coupled to diglyceride− (and monoglyceride−) kinase(s), could achieve AA release and (lyso) phosphatidic acid accumulation. Some properties of these enzymes (subcellular localization, calcium and pH dependence, positional specificity) will be presented.

scholarly journals OsMADS18, a membrane-bound MADS-box transcription factor, modulates plant architecture and the abscisic acid response in rice

2019 ◽  
Vol 70 (15) ◽  
pp. 3895-3909 ◽  
Author(s):  
Xiaoming Yin ◽  
Xiong Liu ◽  
Buxian Xu ◽  
Piaoyin Lu ◽  
Tian Dong ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Plasma Membrane ◽  
Abscisic Acid ◽  
Seedling Growth ◽  
Plant Architecture ◽  
Molecular Mechanisms ◽  
Inhibitory Effect ◽  
Mads Box ◽  
Seed Setting ◽  
Membrane Bound

Abstract The APETALA1 (AP1)/FRUITFULL (FUL)-like transcription factor OsMADS18 plays diverse functions in rice development, but the underlying molecular mechanisms are far from fully understood. Here, we report that down-regulation of OsMADS18 expression in RNAi lines caused a delay in seed germination and young seedling growth, whereas the overexpression of OsMADS18 produced plants with fewer tillers. In targeted OsMADS18 genome-edited mutants (osmads18-cas9), an increased number of tillers, altered panicle size, and reduced seed setting were observed. The EYFP-OsMADS18 (full-length) protein was localized to the nucleus and plasma membrane but the EYFP-OsMADS18-N (N-terminus) protein mainly localized to the nucleus. The expression of OsMADS18 could be stimulated by abscisic acid (ABA), and ABA stimulation triggered the cleavage of HA-OsMADS18 and the translocation of OsMADS18 from the plasma membrane to the nucleus. The inhibitory effect of ABA on seedling growth was less effective in the OsMADS18-overexpressing plants. The expression of a set of ABA-responsive genes was significantly reduced in the overexpressing plants. The phenotypes of transgenic plants expressing EYFP-OsMADS18-N resembled those observed in the osmads18-cas9 mutants. Analysis of the interaction of OsMADS18 with OsMADS14, OsMADS15, and OsMADS57 strongly suggests an essential role for OsMADS18 in rice development.

Exterior and Interior Events in Early Stage of Thrombin-induced Platelet Aggregation

1977 ◽  
Vol 38 (03) ◽  
pp. 0630-0639 ◽  
Author(s):  
Shuichi Hashimoto ◽  
Sachiko Shibata ◽  
Bonro Kobayashi
Keyword(s):  
Molecular Weight ◽  
Enzyme Activity ◽  
Plasma Membrane ◽  
Platelet Aggregation ◽  
Early Stage ◽  
Adenyl Cyclase ◽  
Cellular Component ◽  
Primary Event ◽  
Rabbit Platelets ◽  
Membrane Bound

SummaryTreatment of washed rabbit platelets with 1 u/ml of thrombin at 37° C resulted in a disappearance from platelets of a protein with 250,000 dalton molecular weight which was shown to be originated from plasma membrane. Parallel loss of adenyl cyclase was noted, and both reactions were complete within 30 sec. From the patterns of disc electrophoretograms, the importance of quick suppression of thrombin action in demonstrating the primary event was stressed.Thrombin induced an apparent activation of membrane bound phosphodiesterase. This reaction was also complete within 30 sec. The cellular component which contained the enzyme activity was distinct from plasma membrane. Soluble phosphodiesterase was not influenced by thrombin at all.These reactions required intact platelet cells to react with thrombin, and no reaction was detected when subcellular preparations were treated with thrombin.Possibility of collaboration of changes in externally located synthetic enzyme with those in internally located degrading enzyme in the early phase of thrombin action on platelets was suggested.

Interaction between cortisol and arachidonic acid on the secretion of LH from ovine pituitary tissue

1991 ◽  
Vol 131 (1) ◽  
pp. 87-94 ◽  
Author(s):  
A. W. Nangalama ◽  
G. P. Moberg
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Suppressive Effect ◽  
Inhibitory Effect ◽  
Adrenal Steroids ◽  
Membrane Phospholipids ◽  
Pituitary Tissue ◽  
Receptor Sites ◽  
Lh Release ◽  
Gonadotrophin Releasing Hormone

ABSTRACT In several species, glucocorticoids act directly on the pituitary gonadotroph to suppress the gonadotrophin-releasing hormone (GnRH)-induced secretion of the gonadotrophins, especially LH. A mechanism for this action of these adrenal steroids has not been established, but it appears that the glucocorticoids influence LH release by acting on one or more post-receptor sites. This study investigated whether glucocorticoids disrupt GnRH-induced LH release by altering the liberation of arachidonic acid from plasma membrane phospholipids, a component of GnRH-induced LH release. Using perifused ovine pituitary tissue, it was established that exposure of gonadotrophs to 1–1000 nmol cortisol/l for 4 h or longer significantly reduced GnRH-stimulated LH release with the maximal inhibitory effect being observed after 6 h of exposure to cortisol. This suppressive effect of cortisol could be reversed by administration of arachidonic acid, which in its own right could stimulate LH release from ovine pituitary tissue. Furthermore, the inhibitory effect of cortisol on GnRH-stimulated LH release could be directly correlated with decreased pituitary responsiveness to GnRH-stimulated arachidonic acid liberation, consistent with our hypothesis that glucocorticoids can suppress GnRH-induced secretion of LH by reducing the amount of arachidonic acid available for the exocytotic response of GnRH. Journal of Endocrinology (1991) 131, 87–94

scholarly journals PROBLEMS ASSOCIATED WITH THE DEMONSTRATION BY LEAD METHODS OF ADENOSINE TRIPHOSPHATASE ACTIVITY IN RESIDENT PERITONEAL MACROPHAGES AND EXUDATE MONOCYTES OF THE GUINEA PIG

1973 ◽  
Vol 21 (5) ◽  
pp. 488-498 ◽  
Author(s):  
R. E. POELMANN ◽  
W. T. DAEMS ◽  
E. J. VAN LOHUIZEN
Keyword(s):  
Plasma Membrane ◽  
Guinea Pig ◽  
Microscopic Study ◽  
Heterogeneous Nucleation ◽  
Adenosine Triphosphatase ◽  
Peritoneal Macrophages ◽  
Electron Microscopic ◽  
Adenosine Triphosphatase Activity ◽  
Eosinophilic Granulocytes ◽  
Membrane Bound

This cytochemical and electron microscopic study on peritoneal macrophages of the guinea pig has raised doubts concerning the validity of lead methods for the demonstration of plasma membrane-bound adenosine triphosphatase activity. The problems encountered are inherent in the use of lead ions as a capture reagent. The nonenzymatically formed precipitates reflect sites of heterogeneous nucleation specific for certain kinds of cells, e.g., resident peritoneal macrophages, eosinophilic granulocytes and, to a lesser degree, exudate monocytes. This type of precipitation is also catalyzed on the surface of nonbiologic matrices such as latex particles. Enzymatic processes may well occur, but they cannot be distinguished from nonenzymatic processes.

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