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1.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1862(11): 1287-1299, 2017 Nov.
Article in English | MEDLINE | ID: mdl-27760387

ABSTRACT

The glycerophospholipids phosphatidylethanolamine, phosphatidylglycerol (PG), and cardiolipin (CL) are major structural components of bacterial membranes. In some bacteria, phosphatidylcholine or phosphatidylinositol and its derivatives form part of the membrane. PG or CL can be modified with the amino acid residues lysine, alanine, or arginine. Diacylglycerol is the lipid anchor from which syntheses of phosphorus-free glycerolipids, such as glycolipids, sulfolipids, or homoserine-derived lipids initiate. Many membrane lipids are subject to turnover and some of them are recycled. Other lipids associated with the membrane include isoprenoids and their derivatives such as hopanoids. Ornithine-containing lipids are widespread in Bacteria but absent in Archaea and Eukarya. Some lipids are probably associated exclusively with the outer membrane of many bacteria, i.e. lipopolysaccharides, sphingolipids, or sulfonolipids. For certain specialized membrane functions, specific lipid structures might be required. Upon cyst formation in Azotobacter vinelandii, phenolic lipids are accumulated in the membrane. Anammox bacteria contain ladderane lipids in the membrane surrounding the anammoxosome organelle, presumably to impede the passage of highly toxic compounds generated during the anammox reaction. Considering that present knowledge on bacterial lipids was obtained from only a few bacterial species, we are probably only starting to unravel the full scale of lipid diversity in bacteria. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.


Subject(s)
Bacteria/metabolism , Diglycerides/biosynthesis , Glycerophospholipids/biosynthesis , Lipogenesis , Membrane Lipids/biosynthesis , Diglycerides/chemistry , Diglycerides/classification , Glycerophospholipids/chemistry , Glycerophospholipids/classification , Membrane Lipids/chemistry , Membrane Lipids/classification , Molecular Structure , Structure-Activity Relationship
2.
J Lipid Res ; 54(7): 1798-811, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23641021

ABSTRACT

Circadian clocks regulate the temporal organization of several biochemical processes, including lipid metabolism, and their disruption leads to severe metabolic disorders. Immortalized cell lines acting as circadian clocks display daily variations in [(32)P]phospholipid labeling; however, the regulation of glycerophospholipid (GPL) synthesis by internal clocks remains unknown. Here we found that arrested NIH 3T3 cells synchronized with a 2 h-serum shock exhibited temporal oscillations in a) the labeling of total [(3)H] GPLs, with lowest levels around 28 and 56 h, and b) the activity of GPL-synthesizing and GPL-remodeling enzymes, such as phosphatidate phosphohydrolase 1 (PAP-1) and lysophospholipid acyltransferases (LPLAT), respectively, with antiphase profiles. In addition, we investigated the temporal regulation of phosphatidylcholine (PC) biosynthesis. PC is mainly synthesized through the Kennedy pathway with choline kinase (ChoK) and CTP:phosphocholine cytidylyltranferase (CCT) as key regulatory enzymes. We observed that the PC labeling exhibited daily changes, with the lowest levels every ~28 h, that were accompanied by brief increases in CCT activity and the oscillation in ChoK mRNA expression and activity. Results demonstrate that the metabolisms of GPLs and particularly of PC in synchronized fibroblasts are subject to a complex temporal control involving concerted changes in the expression and/or activities of specific synthesizing enzymes.


Subject(s)
1-Acylglycerophosphocholine O-Acyltransferase/metabolism , Choline Kinase/metabolism , Circadian Rhythm , Fibroblasts/metabolism , Glycerophospholipids/biosynthesis , Phosphatidate Phosphatase/metabolism , Animals , Cells, Cultured , Circadian Clocks , Fibroblasts/cytology , Fibroblasts/enzymology , Mice , NIH 3T3 Cells , Pancreatitis-Associated Proteins
3.
Prog Lipid Res ; 49(1): 46-60, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19703488

ABSTRACT

In the bacterial model organism Escherichia coli only the three major membrane lipids phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin occur, all of which belong to the glycerophospholipids. The amino acid-containing phosphatidylserine is a major lipid in eukaryotic membranes but in most bacteria it occurs only as a minor biosynthetic intermediate. In some bacteria, the anionic glycerophospholipids phosphatidylglycerol and cardiolipin can be decorated with aminoacyl residues. For example, phosphatidylglycerol can be decorated with lysine, alanine, or arginine whereas in the case of cardiolipin, lysine or d-alanine modifications are known. In few bacteria, diacylglycerol-derived lipids can be substituted with lysine or homoserine. Acyl-oxyacyl lipids in which the lipidic part is amide-linked to the alpha-amino group of an amino acid are widely distributed among bacteria and ornithine-containing lipids are the most common version of this lipid type. Only few bacterial groups form glycine-containing lipids, serineglycine-containing lipids, sphingolipids, or sulfonolipids. Although many of these amino acid-containing bacterial membrane lipids are produced in response to certain stress conditions, little is known about the specific molecular functions of these lipids.


Subject(s)
Amino Acids/metabolism , Bacteria/metabolism , Membrane Lipids/metabolism , Bacteria/enzymology , Cardiolipins/biosynthesis , Cardiolipins/metabolism , Diglycerides/biosynthesis , Diglycerides/metabolism , Glycerophospholipids/biosynthesis , Glycerophospholipids/metabolism , Membrane Lipids/biosynthesis , Membrane Lipids/chemistry , Phosphatidylglycerols/biosynthesis , Phosphatidylglycerols/metabolism , Serine C-Palmitoyltransferase/classification , Serine C-Palmitoyltransferase/metabolism , Sphingolipids/biosynthesis , Sphingolipids/metabolism
4.
Neurochem Int ; 47(4): 260-70, 2005 Sep.
Article in English | MEDLINE | ID: mdl-15979208

ABSTRACT

The present study demonstrates that the biosynthesis of phospholipids in the inner nuclear layer cells of the chicken retina displays daily rhythms under constant illumination conditions. The vertebrate retina contains circadian oscillators and photoreceptors (PRCs) that temporally regulate its own physiology and synchronize the whole organism to the daily environmental changes. We have previously reported that chicken photoreceptors and retinal ganglion cells (RGCs) present significant daily variations in their phospholipid biosynthesis under constant illumination conditions. Herein, we demonstrate that cell preparations highly enriched in inner nuclear layer cells also exhibit a circadian-regulated phospholipid labeling after the in vivo administration of [(32)P]phosphate or [(3)H]glycerol both in animals maintained under constant darkness or light for at least 48h. In constant darkness, there was a significant incorporation of both precursors into phospholipids with the highest levels of labeling around midday and dusk. In constant light, the labeling of (32)P-phospholipids was also significantly higher during the day and early night whereas the incorporation of [(3)H]glycerol into phospholipids, that indicates de novo biosynthesis, was greater during the day but probably reflecting a higher precursor availability at those phases. We also measured the in vitro activity of phosphatidate phosphohydrolase and diacylglycerol lipase in preparations obtained from the dark condition. The two enzymes exhibited the highest activity levels late in the day. When we assessed the in vitro incorporation of [(14)C]oleate into different lysophospholipids from samples collected at different phases in constant darkness, reaction catalyzed by lysophospholipid acyltransferases II, labeling showed a complex pattern of daily activity. Taken together, these results demonstrate that the biosynthesis of phospholipids in cells of the chicken retinal inner nuclear layer exhibits a daily rhythmicity under constant illumination conditions, which is controlled by a circadian clock.


Subject(s)
Circadian Rhythm/physiology , Glycerophospholipids/biosynthesis , Light , Neurons/metabolism , Retina/metabolism , 1-Acylglycerophosphocholine O-Acyltransferase/metabolism , Animals , Biological Clocks/physiology , Chickens , Circadian Rhythm/radiation effects , Darkness , Glycerol/metabolism , Glycerophospholipids/radiation effects , Lipoprotein Lipase/metabolism , Neurons/radiation effects , Oleic Acid/metabolism , Phosphates/metabolism , Phosphatidate Phosphatase/metabolism , Photic Stimulation , Photoreceptor Cells, Vertebrate/metabolism , Photoreceptor Cells, Vertebrate/radiation effects , Retina/radiation effects , Retinal Ganglion Cells/metabolism , Retinal Ganglion Cells/radiation effects
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