a b s t r a c tSphingolipids are important membrane components and also regulate cell proliferation and apoptosis. We detected a fast increase of the free sphingobase t18:0 (phytosphinganine) in Arabidopsis leaves after inoculation with an avirulent strain of the bacterial pathogen Pseudomonas syringae pathovar tomato, characterized by host cell death reactions. The induction of phytosphinganine was more transient in virulent interactions lacking cell death reactions, suggesting a positive role of t18:0 in the plants' response to pathogens, e.g. the hypersensitive response. In the mutant sphingobase hydroxylase 1 (sbh1-1), Pseudomonas induced elevated free d18:0 levels. As total t18:0 contents (after hydrolysis of ceramides) were not reduced in sbh1-1, the pathogen-triggered t18:0 increase most likely results from de novo synthesis from d18:0 which would require SBH1.
BackgroundDysregulation of monocyte-macrophage differentiation is a hallmark of vascular and metabolic diseases and associated with persistent low grade inflammation. Plasmalogens represent ether lipids that play a role in diabesity and previous data show diminished plasmalogen levels in obese subjects. We therefore analyzed transcriptomic and lipidomic changes during monocyte-macrophage differentiation in vitro using a bioinformatic approach.MethodsElutriated monocytes from 13 healthy donors were differentiated in vitro to macrophages using rhM-CSF under serum-free conditions. Samples were taken on days 0, 1, 4 and 5 and analyzed for their lipidomic and transcriptomic profiles.ResultsGene expression analysis showed strong regulation of lipidome-related transcripts. Enzymes involved in fatty acid desaturation and elongation were increasingly expressed, peroxisomal and ER stress related genes were induced. Total plasmalogen levels remained unchanged, while the PE plasmalogen species pattern became more similar to circulating granulocytes, showing decreases in PUFA and increases in MUFA. A partial least squares discriminant analysis (PLS/DA) revealed that PE plasmalogens discriminate the stage of monocyte-derived macrophage differentiation. Partial correlation analysis could predict novel potential key nodes including DOCK1, PDK4, GNPTAB and FAM126A that might be involved in regulating lipid and especially plasmalogen homeostasis during differentiation. An in silico transcription analysis of lipid related regulation revealed known motifs such as PPAR-gamma and KLF4 as well as novel candidates such as NFY, RNF96 and Zinc-finger proteins.ConclusionMonocyte to macrophage differentiation goes along with profound changes in the lipid-related transcriptome. This leads to an induction of fatty-acid desaturation and elongation. In their PE-plasmalogen profile macrophages become more similar to granulocytes than monocytes, indicating terminal phagocytic differentiation. Therefore PE plasmalogens may represent potential biomarkers for cell activation. For the underlying transcriptional network we were able to predict a range of novel central key nodes and underlying transcription factors using a bioinformatic approach.
SummaryThe production of the blue dye indigo in plants has been assumed to be a possible route to the introduction of novel coloration into flowers or fibres. As the human cytochrome P450
Using this method, an existing carbapenemase activity can be directly read from the mass spectrum as a ratio of hydrolysed product and substrate, setting an important step towards routine application in clinical laboratories.
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