ABSTRACT
The patatin-related phospholipase A (pPLA) hydrolyzes membrane glycerolipids to produce monoacyl compounds and free fatty acids. Phospholipids are cleaved by pPLAIIα at the sn-1 and sn-2 positions, and galactolipids, including those containing oxophytodienoic acids, can also serve as substrates. Ablation of pPLAIIα decreased lysophosphatidylcholine and lysophosphatidylethanolamine levels, but increased free linolenic acid. pPLAIIα-deficient plants displayed a higher level of jasmonic acid and methyl jasmonate, as well as the oxylipin-biosynthetic intermediates 13-hydroperoxylinolenic acid and 12-oxophytodienoic acid than wild-type (WT) plants. The expression of genes involved in oxylipin production was also higher in the pPLAIIα-deficient mutant than in WT plants. The mutant plants lost water more quickly than WT plants. The stomata of WT and mutant plants responded similarly to abscisic acid. In response to desiccation, the mutant and WT leaves produced abscisic acid at the same rate, but, after 4 h of desiccation, the jasmonic acid level was much higher in mutant than WT leaves. These results indicate that pPLAIIα negatively regulates oxylipin production and suggest a role in the removal of oxidatively modified fatty acids from membranes.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/enzymology , Oxylipins/metabolism , Phospholipases A/metabolism , Water/metabolism , Abscisic Acid/pharmacology , Arabidopsis/drug effects , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Cyclopentanes/metabolism , Droughts , Galactolipids/metabolism , Gene Expression Regulation, Plant/drug effects , Gene Knockout Techniques , Hydrolases , Hydrolysis/drug effects , Lysophospholipids/metabolism , Oxidation-Reduction/drug effects , Phenotype , Phospholipases A/genetics , Plant Leaves/drug effects , Plant Leaves/metabolism , Plant Stomata/drug effects , Plant Stomata/physiology , Substrate Specificity/drug effects , Up-Regulation/drug effectsABSTRACT
48 patients with fractures of the jaw bones were included in this study. Intermaxillary fixation screws were used for tractions between the upper and lower jaw and to regain occlusion relationship, followed by internal rigid fixation. Two days after reduction of the fractures, intermaxillary tractions were carried out and the fixation screws remained for 2 weeks. All the wounds healed primarily with good occlusion. The wounds for screw placement healed well 3 to 5 days after removal of the screws. Excellent occlusion recovered in 45 patients, while in 3 patients, mild open bite developed which returned to normal after 2 weeks of intermaxillary tractions. It is concluded that intermaxillary fixation screws are time saving and efficient in the management of jaw fractures.
