scholarly journals The small molecule fenpropimorph rapidly converts chloroplast membrane lipids to triacylglycerols in Chlamydomonas reinhardtii

2015 ◽  
Vol 6 ◽  
Author(s):  
Hanul Kim ◽  
Sunghoon Jang ◽  
Sangwoo Kim ◽  
Yasuyo Yamaoka ◽  
Daewoong Hong ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Small Molecule ◽  
Membrane Lipids ◽  
Chloroplast Membrane

Membrane lipid metabolism in Chlamydomonas reinhardtii 137+ and Y-1: I. Biochemical localization and characterization of acyltransferase activities

1982 ◽  
Vol 58 (1) ◽  
pp. 469-488
Author(s):  
C.L. Jelsema ◽  
A.S. Michaels ◽  
D.R. Janero ◽  
R.J. Barrnett
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Enzyme Activities ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Light Induction ◽  
Wild Type ◽  
Ph Optimum ◽  
Acyltransferase Activity ◽  
Photosynthetic Membranes ◽  
Chloroplast Membrane

The acyltransferases involved in the synthesis of the chloroplast membrane glycerolipids were analysed biochemically in dark-grown and greening Chlamydomonas reinhardtii y-1 as well as in the synchronous wild-type algae (strain 137+) and wild-type membranes. Using oleoyl-CoA as a substrate, three acyltransferase enzyme activities were detected. Glycerol-3-phosphate (glycerol-3-P) acyltransferase exhibited a pH optimum of 8.0 and was inhibited by addition of N-ethylmaleimide (MalNEt). Lysophosphatidate (PtdLys) acyltransferase exhibited a pH optimum of 7.0 and was not affected by the addition of MalNEt. From preliminary analyses, the activity at pH 5.5 appeared to be associated with dihydroxyacetone phosphate acyltransferase activity. Both glycerol-3-P and PtdLys acyltransferases were analysed further and found to be present in dark-grown and light-induced y-1 cells as well as in synchronous 137+ cells and their photosynthetic membranes. Both enzyme activities were enriched at least 10-fold in the photosynthetic membranes of 137+ chloroplasts relative to the activities present in the whole cells. This enrichment is indicative of their intrinsic localization in the thylakoids, suggesting that the photosynthetic membranes exhibit a greater degree of autonomy with respect to the synthesis of their membrane lipids than previously reported. A role for glycerol-3-P and PtdLys acyltransferases in the synthesis of the chloroplast membrane lipids is suggested further by the increases in both enzyme activities coincident with and preceding thylakoid biogenesis following light induction of dark-grown y-1 cells. Increased acyltransferase activity preceded the increase in the chlorophyll content of greening y-1 cells, which is a generally accepted marker for thylakoid synthesis. The increase in the PtdLys acyltransferase activity upon light-induction of the y-1 cells was both more immediate and more dramatic than the increase in glycerol-3-P acyltransferase activity. PtdLys acyltransferase activity was negligible in dark-grown cells and the dramatic increase upon light induction may be important in the subsequent initiation of chloroplast membrane lipid synthesis. On the basis of the localization of acyltransferase enzyme activities to the photosynthetic membranes of 137+ cells and the increase in acyltransferase activity both preceding and occurring in concert with thylakoid synthesis, we propose a direct role for the photosynthetic membranes in the synthesis of their membrane lipid components.

scholarly journals Small-Molecule Modulation of Lipid-Dependent Cellular Processes against Cancer: Fats on the Gunpoint

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Aswin T. Srivatsav ◽  
Manjari Mishra ◽  
Shobhna Kapoor
Keyword(s):  
Small Molecule ◽  
Drug Targets ◽  
Membrane Lipids ◽  
Membrane Microdomains ◽  
Critical Function ◽  
Future Directions ◽  
Cellular Processes ◽  
Cancer Phenotypes ◽  
Critical Intervention ◽  
Distinct Membrane

Lipid cell membrane composed of various distinct lipids and proteins act as a platform to assemble various signaling complexes regulating innumerous cellular processes which are strongly downregulated or altered in cancer cells emphasizing the still-underestimated critical function of lipid biomolecules in cancer initiation and progression. In this review, we outline the current understanding of how membrane lipids act as signaling hot spots by generating distinct membrane microdomains called rafts to initiate various cellular processes and their modulation in cancer phenotypes. We elucidate tangible drug targets and pathways all amenable to small-molecule perturbation. Ranging from targeting membrane rafts organization/reorganization to rewiring lipid metabolism and lipid sorting in cancer, the work summarized here represents critical intervention points being attempted for lipid-based anticancer therapy and future directions.

scholarly journals Purification of the chloroplast-membrane dicyclohexylcarbodi-imide-binding proteolipid by ion-exchange chromatography

1979 ◽  
Vol 177 (2) ◽  
pp. 687-692 ◽  
Author(s):  
K Sigrist-Nelson ◽  
A Azzi
Keyword(s):  
Ion Exchange ◽  
Major Part ◽  
Membrane Lipids ◽  
Binding Protein ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Chloroplast Membranes ◽  
Rapid Procedure ◽  
Chloroplast Membrane ◽  
Endogenous Lipid

An efficient, mild and rapid procedure is reported for the separation of the dicyclohexyl-carbodi-imide-binding protein of chloroplast membranes from endogenous lipid components. By the use of ion-exchange chromatography the chloroplast proteolipid can be successfully separated from the major part of chlorophyll and other membrane lipids while being retained in a butan-1-ol milieu.

Structure Versus Activity of Substituted Pyridazinones as Related to Mechanism of Action

Weed Science ◽  
1976 ◽  
Vol 24 (6) ◽  
pp. 579-582 ◽  
Author(s):  
J. B. St. John ◽  
J. L. Hilton
Keyword(s):  
Fatty Acids ◽  
Phenyl Ring ◽  
Membrane Lipids ◽  
Carotenoid Biosynthesis ◽  
Polar Lipids ◽  
Maximum Effect ◽  
Hill Reaction ◽  
Methyl Substitution ◽  
Chloroplast Membrane ◽  
The Hill

In at least three metabolic processes in wheat (Triticum aestivumL. var. ‘Arthur’) shoots inhibitory activity can be related to the chemical structure of substituted pyridazinones. Inhibitory activities include: inhibition of the Hill reaction and photosynthetic CO2fixation; inhibition of carotenoid biosynthesis accompanied by photodestruction of chlorophyll; and interference with the formation of chloroplast membrane polar lipids. The parent compound, pyrazon [5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone], inhibits the Hill reaction and photosynthetic CO2fixation. Trifluoromethyl substitution of the phenyl ring of pyrazon, mono-methyl substitution of the amine, or substitutions at both positions result in inhibition of carotenoid biosynthesis. However, both substitutions are required for maximum effect. Substitutions onto the molecular structure of pyrazon are also related to alterations in the formation of membrane polar lipids. Dimethyl substitution of the amine of pyrazon is related to a decrease in linolenic acid accompanied by an increase in linoleic acid without a shift in the relative proportion of saturated to unsaturated fatty acids of the membrane lipids. The trifluoromethyl substitution of the phenyl ring and mono-methyl substitution of the amine are related to a shift toward a higher proportion of saturated fatty acids of chloroplast membrane lipids. Results obtained with diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] and with dark-grown wheat tissue indicated that activity of the pyridazinones on the formation of membrane lipids was probably not related to inhibition of the Hill reaction.

THE INFLUENCE OF FATTY ACID UNSATURATION ON FLUIDITY AND MOLECULAR PACKING OF CHLOROPLAST MEMBRANE LIPIDS

1979 ◽  
pp. 375-389 ◽  
Author(s):  
David G. Bishop ◽  
Janette R. Kenrick ◽  
James H. Bayston ◽  
Athol S. Macpherson ◽  
Stanley R. Johns ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Membrane Lipids ◽  
Molecular Packing ◽  
Fatty Acid Unsaturation ◽  
Chloroplast Membrane
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