Chronic intermittent hypoxia upregulates genes of lipid biosynthesis in obese mice

2005 ◽  
Vol 99 (5) ◽  
pp. 1643-1648 ◽  
Author(s):  
Jianguo Li ◽  
Dmitry N. Grigoryev ◽  
Shui Qing Ye ◽  
Laura Thorne ◽  
Alan R. Schwartz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Fatty Liver ◽  
Real Time ◽  
Real Time Pcr ◽  
Intermittent Hypoxia ◽  
Fatty Acid Biosynthesis ◽  
Lipid Biosynthesis ◽  
Chronic Intermittent Hypoxia ◽  
Acid Biosynthesis

Obstructive sleep apnea (OSA), a condition tightly linked to obesity, leads to chronic intermittent hypoxia (CIH) during sleep. There is emerging evidence that OSA is independently associated with insulin resistance and fatty liver disease, suggesting that OSA may affect hepatic lipid metabolism. To test this hypothesis, leptin-deficient obese ( ob/ob) mice were exposed to CIH during the light phase (9 AM–9 PM) for 12 wk. Liver lipid content and gene expression profile in the liver (Affymetrix 430 GeneChip with real-time PCR validation) were determined on completion of the exposure. CIH caused a 30% increase in triglyceride and phospholipid liver content ( P < 0.05), whereas liver cholesterol content was unchanged. Gene expression analysis showed that CIH upregulated multiple genes controlling 1) cholesterol and fatty acid biosynthesis [malic enzyme and acetyl coenzyme A (CoA) synthetase], 2) predominantly fatty acid biosynthesis (acetyl-CoA carboxylase and stearoyl-CoA desaturases 1 and 2), and 3) triglyceride and phospholipid biosynthesis (mitochondrial glycerol-3-phosphate acyltransferase). A majority of overexpressed genes were transcriptionally regulated by sterol regulatory element-binding protein (SREBP) 1, a master regulator of lipogenesis. A 2.8-fold increase in SREBP-1 gene expression in CIH was confirmed by real-time PCR ( P = 0.001). Expression of major genes of cholesterol biosynthesis, SREBP-2 and 3-hydroxy-3-methylglutaryl-CoA reductase, was unchanged. In conclusion, we have shown that CIH may exacerbate preexisting fatty liver of obesity via upregulation of the pathways of lipid biosynthesis in the liver.

The effect of cadmium on lipid and fatty acid biosynthesis in tomato leaves

Biologia ◽  
2008 ◽  
Vol 63 (1) ◽  
Author(s):  
Wided Ben Ammar ◽  
Issam Nouairi ◽  
Mokhtar Zarrouk ◽  
Fatma Jemal
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Acid Content ◽  
Fatty Acid Biosynthesis ◽  
Fatty Acid Content ◽  
Lipid Biosynthesis ◽  
Lipid Classes ◽  
Acetate Incorporation ◽  
Acid Biosynthesis ◽  
Tomato Plants

AbstractThis research aims to examine the effect of cadmium uptake on lipid composition and fatty acid biosynthesis, in young leaves of tomato treated seedlings (Lycopersicon esculentum cv. Ibiza F1). Results in membrane lipids investigations revealed that high cadmium concentrations affect the main lipid classes, leading to strong changes in their composition and fatty acid content. Thus, the exposure of tomato plants to cadmium caused a concentration-related decrease in the unsaturated fatty acid content, resulting in a lower degree of fatty acid unsaturation. The level of lipid peroxides was significantly enhanced at high Cd concentrations. Studies of the lipid metabolism using radioactive labelling with [1-14C]acetate as a major precursor of lipid biosynthesis, showed that levels of radioactivity incorporation in total lipids as well as in all lipid classes were lowered by Cd doses. In total lipid fatty acids, [1-14C]acetate incorporation was reduced in tri-unsaturated fatty acids (C16:3 and C18:3); While it was enhanced in the palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0) and linoleic (C18:2) acids. [1-14C]acetate incorporation into C16:3 and C18:3 of galactolipids [monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG)] and some phospholipids [phosphatidylcholine (PC) and phosphatidylglycerol (PG)] was inhibited by Cd stress. Our results showed that in tomato plants, cadmium stress provoked an inhibition of polar lipid biosynthesis and reduced fatty acid desaturation process.

Curcumin improves alcoholic fatty liver by inhibiting fatty acid biosynthesis

2017 ◽  
Vol 328 ◽  
pp. 1-9 ◽  
Author(s):  
Chang Guo ◽  
Jingfan Ma ◽  
Qionghong Zhong ◽  
Mengyuan Zhao ◽  
Tianxing Hu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Liver ◽  
Fatty Acid Biosynthesis ◽  
Acid Biosynthesis ◽  
Alcoholic Fatty Liver

scholarly journals Amino Acids Attenuate Insulin Action on Gluconeogenesis and Promote Fatty Acid Biosynthesis via mTORC1 Signaling Pathway in trout Hepatocytes

2015 ◽  
Vol 36 (3) ◽  
pp. 1084-1100 ◽  
Author(s):  
Weiwei Dai ◽  
Stéphane Panserat ◽  
Elisabeth Plagnes-Juan ◽  
Iban Seiliez ◽  
Sandrine Skiba-Cassy
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Fatty Acid ◽  
P38 Mapk ◽  
Insulin Action ◽  
Fatty Acid Biosynthesis ◽  
Acute Administration ◽  
Dependent Manner ◽  
Acid Biosynthesis ◽  
Mtorc1 Signaling

Background/Aims: Carnivores exhibit poor utilization of dietary carbohydrates and glucose intolerant phenotypes, yet it remains unclear what are the causal factors and underlying mechanisms. We aimed to evaluate excessive amino acids (AAs)-induced effects on insulin signaling, fatty acid biosynthesis and glucose metabolism in rainbow trout and determine the potential involvement of mTORC1 and p38 MAPK pathway. Methods: We stimulated trout primary hepatocytes with different AA levels and employed acute administration of rapamycin to inhibit mTORC1 activation. Results: Increased AA levels enhanced the phosphorylation of ribosomal protein S6 kinase (S6K1), S6, and insulin receptor substrate 1 (IRS-1) on Ser302 but suppressed Akt and p38 phosphorylation; up-regulated the expression of genes related to gluconeogenesis and fatty acid biosynthesis. mTORC1 inhibition not only inhibited the phosphorylation of mTORC1 downstream targets, but also blunted IRS-1 Ser302 phosphorylation and restored excessive AAs-suppressed Akt phosphorylation. Rapamycin also inhibited fatty acid biosynthetic and gluconeogenic gene expression. Conclusion: High levels of AAs up-regulate hepatic fatty acid biosynthetic gene expression through an mTORC1-dependent manner, while attenuate insulin-mediated repression of gluconeogenesis through elevating IRS-1 Ser302 phosphorylation, which in turn impairs Akt activation and thereby weakening insulin action. We propose that p38 MAPK probably also involves in these AAs-induced metabolic changes.

scholarly journals Morphological Features and Cold-Response Gene Expression in Mesophilic Bacillus cereus Group and Psychrotolerant Bacillus cereus Group under Low Temperature

2021 ◽  
Vol 9 (6) ◽  
pp. 1255
Author(s):  
Kyung-Min Park ◽  
Hyun-Jung Kim ◽  
Min-Sun Kim ◽  
Minseon Koo
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Low Temperature ◽  
Bacillus Cereus ◽  
Low Temperatures ◽  
Fatty Acid Biosynthesis ◽  
Morphological Changes ◽  
Growth Strategies ◽  
Acid Biosynthesis ◽  
Bacillus Cereus Group

At low temperatures, psychrotolerant B. cereus group strains exhibit a higher growth rate than mesophilic strains do. However, the different survival responses of the psychrotolerant strain (BCG34) and the mesophilic strain (BCGT) at low temperatures are unclear. We investigated the morphological and genomic features of BCGT and BCG34 to characterize their growth strategies at low temperatures. At low temperatures, morphological changes were observed only in BCGT. These morphological changes included the elongation of rod-shaped cells, whereas the cell shape in BCG34 was unchanged at the low temperature. A transcriptomic analysis revealed that both species exhibited different growth-related traits during low-temperature growth. The BCGT strain induces fatty acid biosynthesis, sulfur assimilation, and methionine and cysteine biosynthesis as a survival mechanism in cold systems. Increases in energy metabolism and fatty acid biosynthesis in the mesophilic B. cereus group strain might explain its ability to grow at low temperatures. Several pathways involved in carbohydrate mechanisms were downregulated to conserve the energy required for growth. Peptidoglycan biosynthesis was upregulated, implying that a change of gene expression in both RNA-Seq and RT-qPCR contributed to sustaining its growth and rod shape at low temperatures. These results improve our understanding of the growth response of the B. cereus group, including psychrotolerant B. cereus group strains, at low temperatures and provide information for improving bacterial inhibition strategies in the food industry.

Lipid Biosynthesis Inhibitors

Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 435-449 ◽  
Author(s):  
John W. Gronwald
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Higher Plants ◽  
Lipid Biosynthesis ◽  
Chloroplast Envelope ◽  
Acetyl Coa Carboxylase ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Surface Lipids

Five classes of herbicides (carbamothioates, chloroacetamides, substituted pyridazinones, cyclohexanediones, and aryloxyphenoxypropionic acids) have been reported to inhibit lipid biosynthesis in higher plants. Carbamothioates impair the synthesis of surface lipids (waxes, cutin, suberin). These effects have been attributed to the ability of this herbicide class to inhibit one or more acyl-CoA elongases. Though as yet poorly characterized, these enzymes are associated with the endoplasmic reticulum and catalyze the condensation of malonyl-CoA with fatty acid acyl-CoA substrates to form very long-chain fatty acids used in the synthesis of surface lipids. There is contradictory evidence regarding the effects of chloroacetamide herbicides on de novo fatty acid biosynthesis. Selected substituted pyridazinones decrease the degree of unsaturation of plastidic galactolipids. This effect is attributed to the ability of selected members of this herbicide class to inhibit fatty acid desaturases which are thought to be located in the chloroplast envelope. Aryloxyphenoxypropionic acid and cyclohexanedione herbicides inhibit de novo fatty acid biosynthesis in grasses. The target site for these herbicide classes is the enzyme acetyl-CoA carboxylase which is found in the stroma of plastids. In most cases, selectivity between grasses and dicots is expressed at this site. Aryloxyphenoxypropionic acids and cyclohexanediones are reversible, linear, noncompetitive inhibitors of acetyl-CoA carboxylase from grasses. Both classes are also mutually exclusive inhibitors of grass acetyl-CoA carboxylase which suggests that they bind at a common domain on the enzyme.

Inhibition of early steps of de novo fatty-acid biosynthesis by different xenobiotica

1991 ◽  
Vol 81 (2) ◽  
pp. 251-255
Author(s):  
Manfred Focke ◽  
Andrea Feld ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Acid Biosynthesis
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