The Photoinhibition of the Photosystem II Complex is Regulated by Unsáturation of Fatty Acids in Membrane Lipids

1998 ◽  
pp. 1777-1782
Author(s):  
N. Murata ◽  
Z. Gombos ◽  
E. Kanervo ◽  
K. Sippola ◽  
E.-M. Aro
Keyword(s):  
Fatty Acids ◽  
Photosystem Ii ◽  
Membrane Lipids

scholarly journals Specific Incorporation of Polyunsaturated Fatty Acids into the sn-2 Position of Phosphatidylglycerol Accelerates Photodamage to Photosystem II under Strong Light

2021 ◽  
Vol 22 (19) ◽  
pp. 10432
Author(s):  
Haruhiko Jimbo ◽  
Koki Yuasa ◽  
Kensuke Takagi ◽  
Takashi Hirashima ◽  
Sumie Keta ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Photosystem Ii ◽  
Polyunsaturated Fatty Acids ◽  
Membrane Lipids ◽  
Monounsaturated Fatty Acids ◽  
Oxygen Evolving Complex ◽  
Strong Light ◽  
Photosynthetic Organisms ◽  
Oxygen Evolving ◽  
Synechocystis Sp

Free fatty acids (FFAs) are generated by the reaction of lipases with membrane lipids. Generated polyunsaturated fatty acids (PUFAs) containing more than two double bonds have toxic effects in photosynthetic organisms. In the present study, we examined the effect of exogenous FFAs in the growth medium on the activity of photosystem II (PSII) under strong light in the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis). PUFAs but not monounsaturated fatty acids accelerated the rate of photodamage to PSII by inactivating electron transfer at the oxygen-evolving complex. Moreover, supplemented PUFAs were specifically incorporated into the sn-2 position of phosphatidylglycerol (PG), which usually contains C16 fatty acids at the sn-2 position in Synechocystis cells. The disruption of the gene for an acyl-ACP synthetase reduced the effect of PUFAs on the photoinhibition of PSII. Thus, the specific incorporation of PUFAs into PG molecules requires acyl-ACP synthetase and leads to an unstable PSII, thereby accelerating photodamage to PSII. Our results are a breakthrough into elucidating the molecular mechanism of the toxicity of PUFAs to photosynthetic organisms.

scholarly journals The effects of galactolipid depletion on the structure of a photosynthetic membrane.

1986 ◽  
Vol 103 (4) ◽  
pp. 1337-1347 ◽  
Author(s):  
J S Jacob ◽  
K R Miller
Keyword(s):  
Fatty Acids ◽  
Photosystem Ii ◽  
Membrane Structure ◽  
Membrane Lipids ◽  
Freeze Fracture ◽  
Membrane System ◽  
Water Soluble ◽  
Membrane Composition ◽  
Higher Plant ◽  
Photosynthetic Membrane

The galactolipids monogalactosyldiglyceride and digalactosyldiglyceride together comprise more than 77% of the photosynthetic membrane lipids of higher plant chloroplasts. We have isolated a lipase from the chloroplasts of runner beans (Phaseolus vulgaris) which is highly specific for these galactolipids. This galactolipase promotes the hydrolysis of monogalactosyldiglyceride and digalactosyldiglyceride, in the process liberating two free fatty acids into the membrane bilayer, leaving the residual galactosyl glyceride group to diffuse into the aqueous bulk phase. Isolated spinach photosynthetic membranes were treated with this enzyme preparation and changes in membrane composition were studied with thin layer chromatography (for lipids), gel electrophoresis (proteins), and freeze-etching (membrane structure). After 30 min of lipolysis, nearly 100% of the galactolipids had been converted into membrane-associated fatty acids and water-soluble galactosyl glycerides. SDS PAGE showed that two proteins, one of which is possibly associated with the reaction center of photosystem II, were removed by the treatment. Despite the minor nature of changes in membrane protein composition, freeze-fracture and freeze-etch studies showed that striking changes in membrane structure had taken place. The large freeze-fracture particle on the E fracture face had disappeared in stacked regions of the membrane system. In addition, a tetrameric particle visible at the inner surface of the membrane had apparently dissociated into individual monomeric particles. The fact that these two structures are so dramatically affected by the loss of galactolipids strongly suggests that these lipids play a crucial role in maintaining their structure. Both structures are believed to be different views of the same transmembrane unit: a membrane-spanning complex associated with photosystem II. Our results are consistent with two possible interpretations: the intramembrane particles may be lipidic in nature, and hence lipolysis causes their disappearance; or galactolipids are necessary for the organization of a complex photosystem II-associated structure which is composed of a number of different molecular species.

scholarly journals Heat stress elicits remodeling in the anther lipidome of peanut

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zolian S. Zoong Lwe ◽  
Ruth Welti ◽  
Daniel Anco ◽  
Salman Naveed ◽  
Sachin Rustgi ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Heat Stress ◽  
Fatty Acid ◽  
Membrane Lipids ◽  
Fatty Acid Desaturase ◽  
Susceptible Genotype ◽  
Unsaturated Lipid ◽  
Lipid Species ◽  
Lipid Unsaturation ◽  
Fatty Acid Amount

AbstractUnderstanding the changes in peanut (Arachis hypogaea L.) anther lipidome under heat stress (HT) will aid in understanding the mechanisms of heat tolerance. We profiled the anther lipidome of seven genotypes exposed to ambient temperature (AT) or HT during flowering. Under AT and HT, the lipidome was dominated by phosphatidylcholine (PC), phosphatidylethanolamine (PE), and triacylglycerol (TAG) species (> 50% of total lipids). Of 89 lipid analytes specified by total acyl carbons:total carbon–carbon double bonds, 36:6, 36:5, and 34:3 PC and 34:3 PE (all contain 18:3 fatty acid and decreased under HT) were the most important lipids that differentiated HT from AT. Heat stress caused decreases in unsaturation indices of membrane lipids, primarily due to decreases in highly-unsaturated lipid species that contained 18:3 fatty acids. In parallel, the expression of Fatty Acid Desaturase 3-2 (FAD3-2; converts 18:2 fatty acids to 18:3) decreased under HT for the heat-tolerant genotype SPT 06-07 but not for the susceptible genotype Bailey. Our results suggested that decreasing lipid unsaturation levels by lowering 18:3 fatty-acid amount through reducing FAD3 expression is likely an acclimation mechanism to heat stress in peanut. Thus, genotypes that are more efficient in doing so will be relatively more tolerant to HT.

scholarly journals Lipidomics Provides New Insight into Pathogenesis and Therapeutic Targets of the Ischemia—Reperfusion Injury

2021 ◽  
Vol 22 (6) ◽  
pp. 2798
Author(s):  
Zoran Todorović ◽  
Siniša Đurašević ◽  
Maja Stojković ◽  
Ilijana Grigorov ◽  
Slađan Pavlović ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Time Course ◽  
Membrane Lipids ◽  
Lipid Analysis ◽  
Cell Damage ◽  
Ischemia Reperfusion ◽  
Enzyme Inactivation ◽  
Critical Event ◽  
Tissue Ischemia ◽  
Insight Into

Lipids play an essential role in both tissue protection and damage. Tissue ischemia creates anaerobic conditions in which enzyme inactivation occurs, and reperfusion can initiate oxidative stress that leads to harmful changes in membrane lipids, the formation of aldehydes, and chain damage until cell death. The critical event in such a series of harmful events in the cell is the unwanted accumulation of fatty acids that leads to lipotoxicity. Lipid analysis provides additional insight into the pathogenesis of ischemia/reperfusion (I/R) disorders and reveals new targets for drug action. The profile of changes in the composition of fatty acids in the cell, as well as the time course of these changes, indicate both the mechanism of damage and new therapeutic possibilities. A therapeutic approach to reperfusion lipotoxicity involves attenuation of fatty acids overload, i.e., their transport to adipose tissue and/or inhibition of the adverse effects of fatty acids on cell damage and death. The latter option involves using PPAR agonists and drugs that modulate the transport of fatty acids via carnitine into the interior of the mitochondria or the redirection of long-chain fatty acids to peroxisomes.

scholarly journals Rapid Mobilization of Membrane Lipids in Wheat Leaf Sheaths During Incompatible Interactions with Hessian Fly

2012 ◽  
Vol 25 (7) ◽  
pp. 920-930 ◽  
Author(s):  
Lieceng Zhu ◽  
Xuming Liu ◽  
Haiyan Wang ◽  
Chitvan Khajuria ◽  
John C. Reese ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Membrane Lipids ◽  
Hessian Fly ◽  
Delayed Response ◽  
Lipid Species ◽  
Polymerase Chain ◽  
Wheat Lines ◽  
Defense Molecules ◽  
Compatible Interactions ◽  
Incompatible Interactions

Hessian fly (HF) is a biotrophic insect that interacts with wheat on a gene-for-gene basis. We profiled changes in membrane lipids in two isogenic wheat lines: a susceptible line and its backcrossed offspring containing the resistance gene H13. Our results revealed a 32 to 45% reduction in total concentrations of 129 lipid species in resistant plants during incompatible interactions within 24 h after HF attack. A smaller and delayed response was observed in susceptible plants during compatible interactions. Microarray and real-time polymerase chain reaction analyses of 168 lipid-metabolism-related transcripts revealed that the abundance of many of these transcripts increased rapidly in resistant plants after HF attack but did not change in susceptible plants. In association with the rapid mobilization of membrane lipids, the concentrations of some fatty acids and 12-oxo-phytodienoic acid (OPDA) increased specifically in resistant plants. Exogenous application of OPDA increased mortality of HF larvae significantly. Collectively, our data, along with previously published results, indicate that the lipids were mobilized through lipolysis, producing free fatty acids, which were likely further converted into oxylipins and other defense molecules. Our results suggest that rapid mobilization of membrane lipids constitutes an important step for wheat to defend against HF attack.

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