scholarly journals Impact of Unusual Fatty Acid Synthesis on Futile Cycling through β-Oxidation and on Gene Expression in Transgenic Plants

2003 ◽  
Vol 134 (1) ◽  
pp. 432-442 ◽  
Author(s):  
Laurence Moire ◽  
Enea Rezzonico ◽  
Simon Goepfert ◽  
Yves Poirier
2012 ◽  
Vol 78 (6) ◽  
pp. 1865-1875 ◽  
Author(s):  
Anna E. Nikitkova ◽  
Elaine M. Haase ◽  
M. Margaret Vickerman ◽  
Steven R. Gill ◽  
Frank A. Scannapieco

ABSTRACTStreptococcus gordonii, an important primary colonizer of dental plaque biofilm, specifically binds to salivary amylase via the surface-associated amylase-binding protein A (AbpA). We hypothesized that a function of amylase binding toS. gordoniimay be to modulate the expression of chromosomal genes, which could influence bacterial survival and persistence in the oral cavity. Gene expression profiling by microarray analysis was performed to detect genes inS. gordoniistrain CH1 that were differentially expressed in response to the binding of purified human salivary amylase versus exposure to purified heat-denatured amylase. Selected genes found to be differentially expressed were validated by quantitative reverse transcription-PCR (qRT-PCR). Five genes from the fatty acid synthesis (FAS) cluster were highly (10- to 35-fold) upregulated inS. gordoniiCH1 cells treated with native amylase relative to those treated with denatured amylase. AnabpA-deficient strain ofS. gordoniiexposed to amylase failed to show a response in FAS gene expression similar to that observed in the parental strain. Predicted phenotypic effects of amylase binding toS. gordoniistrain CH1 (associated with increased expression of FAS genes, leading to changes in fatty acid synthesis) were noted; these included increased bacterial growth, survival at low pH, and resistance to triclosan. These changes were not observed in the amylase-exposedabpA-deficient strain, suggesting a role for AbpA in the amylase-induced phenotype. These results provide evidence that the binding of salivary amylase elicits a differential gene response inS. gordonii, resulting in a phenotypic adjustment that is potentially advantageous for bacterial survival in the oral environment.


2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S9-S10
Author(s):  
Brooklyn McGrew ◽  
Aman Shrivastava ◽  
Philip Fernandes ◽  
Lubaina Ehsan ◽  
Yash Sharma ◽  
...  

Abstract Background Candidate markers for Crohn’s Disease (CD) may be identified via gene expression-based construction of metabolic networks (MN). These can computationally describe gene-protein-reaction associations for entire tissues and also predict the flux of reactions (rate of turnover of specific molecules via a metabolic pathway). Recon3D is the most comprehensive human MN to date. We used publicly available CD transcriptomic data along with Recon3D to identify metabolites as potential diagnostic and prognostic biomarkers. Methods Terminal ileal gene expression profiles (36,372 genes; 218 CD. 42 controls) from the RISK cohort (Risk Stratification and Identification of Immunogenetic and Microbial Markers of Rapid Disease Progression in Children with Crohn’s Disease) and their transcriptomic abundances were used. Recon3D was pruned to only include RISK dataset transcripts which determined metabolic reaction linkage with transcriptionally active genes. Flux balance analysis (FBA) was then run using RiPTiDe with context specific transcriptomic data to further constrain genes (Figure 1). RiPTiDe was independently run on transcriptomic data from both CD and controls. From the pruned and constricted MN obtained, reactions were extracted for further analysis. Results After applying the necessary constraints to modify Recon3D, 527 CD and 537 control reactions were obtained. Reaction comparison with a publicly available list of healthy small intestinal epithelial reactions (n=1282) showed an overlap of 80 CD and 84 control reactions. These were then further grouped based on their metabolic pathways. RiPTiDe identified context specific metabolic pathway activity without supervision and the percentage of forward, backward, and balanced reactions for each metabolic pathway (Figure 2). The metabolite concentrations in the small intestine was altered among CD patients. Notably, the citric acid cycle and malate-aspartate shuttle were affected, highlighting changes in mitochondrial metabolic pathways. This is illustrated by changes in the number of reactions at equilibrium between CD and control. Conclusions The results are relevant as cytosolic acetyl-CoA is needed for fatty acid synthesis and is obtained by removing citrate from the citric acid cycle. An intermediate removal from the cycle has significant cataplerotic effects. The malate-aspartate shuttle also allows electrons to move across the impermeable membrane in the mitochondria (fatty acid synthesis location). These findings are reported by previously published studies where gene expression for fatty acid synthesis is altered in CD patients along with mitochondrial metabolic pathway changes, resulting in altered cell homeostasis. In-depth analysis is currently underway with our work supporting the utility of potential metabolic biomarkers for CD diagnosis, management and improved care.


Animals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 467 ◽  
Author(s):  
Ahmed A. Saleh ◽  
Abeer A. Kirrella ◽  
Safaa E. Abdo ◽  
Mahmoud M. Mousa ◽  
Nemat A. Badwi ◽  
...  

The present study was conducted to examine that impact of dietary xylanase (Xyl) and arabinofuranosidase (Abf) supplementation on the performance, protein and fat digestibility, the lipid peroxidation, the plasma biochemical traits, and the immune response of broilers. A total of 480, un-sexed, and one-day-old broilers (Ross 308) were randomly divided into three treatments with eight replicates, where chicks in the first treatment were fed basal diets and served as the control, chicks in the second treatment were fed diets formulated with reductions of 90 kcal/kg, and chicks in the third treatment were fed the same formulated diets used in the second group as well as the Xyl and Abf combination (Rovabio® Advance). Feed intake was decreased by the low energy diet, leading to an enhancement in feed efficiency enzyme supplementation in the low energy diet (p < 0.015). Both protein and fat digestibility were improved (p < 0.047) due to enzyme supplementation. Moreover, enzyme supplementation increased muscle total lipids content and decreased muscle thiobarbituric acid retroactive substance content. Furthermore, diets supplemented with Xyl and Abf exhibited an increase in antibody titers against the Newcastle disease virus (p < 0.026). In addition, enzyme supplementation increased gene expression related to growth and gene expression related to fatty acid synthesis. It could be concluded that dietary Xyl and Abf supplementation had beneficial impacts on growth, nutrient digestibility, lipid peroxidation, immune response, and gene expressions related to growth and fatty acid synthesis in broiler chickens fed low-energy diets.


2021 ◽  
Author(s):  
Sumie Eto ◽  
Rumie Matsumura ◽  
Mai Fujimi ◽  
Yasuhiro Shimane ◽  
Samuel Berhanu ◽  
...  

Phospholipid synthesis is a fundamental process that promotes cell propagation and, presently, is the most challenging issue in artificial cell research aimed at reconstituting living cells from biomolecules. Here, we constructed a cell-free phospholipid synthesis system that combines in vitro fatty acid synthesis and a cell-free gene expression system that synthesizes acyltransferases for phospholipid synthesis. Fatty acids were synthesized from acetyl-CoA and malonyl-CoA, then continuously converted into phosphatidic acids by the cell-free synthesized acyltransferases. Because the system can avoid the accumulation of synthetic intermediates that suppress the reaction, the yield of phospholipid has significantly improved from previous schemes (up to 400 μM). Additionally, by adding enzymes for recycling CoA, we synthesized phosphatidic acids from acetic acid and bicarbonate as carbon sources. The constructed system is available to express the genes from pathogenic bacteria and to analyze the synthesized phospholipids. By encapsulating our system inside giant vesicles, it would be possible to construct the artificial cells in which the membrane grows and divides sustainably.


2014 ◽  
Vol 117 (11) ◽  
pp. 1337-1348 ◽  
Author(s):  
Daisuke Fukuoka ◽  
Fumiaki Okahara ◽  
Kohjiro Hashizume ◽  
Kiyotaka Yanagawa ◽  
Noriko Osaki ◽  
...  

Obesity is now a worldwide health problem. Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone that is secreted following the ingestion of food and modulates energy metabolism. Previous studies reported that lowering diet-induced GIP secretion improved energy homeostasis in animals and humans, and attenuated diet-induced obesity in mice. Therefore, food-derived GIP regulators may be used in the development of foods that prevent obesity. Rice bran oil and its components are known to have beneficial effects on health. Therefore, the aim of the present study was to clarify the effects of the oil-soluble components of rice bran on postprandial GIP secretion and obesity in mice. Triterpene alcohols [cycloartenol (CA) and 24-methylene cycloartanol (24Me)], β-sitosterol, and campesterol decreased the diet-induced secretion of GIP in C57BL/6J mice. Mice fed a high-fat diet supplemented with a triterpene alcohol and sterol preparation (TASP) from rice bran for 23 wk gained less weight than control mice. Indirect calorimetry revealed that fat utilization was higher in TASP-fed mice than in control mice. Fatty acid oxidation-related gene expression in the muscles of mice fed a TASP-supplemented diet was enhanced, whereas fatty acid synthesis-related gene expression in the liver was suppressed. The treatment of HepG2 cells with CA and 24Me decreased the gene expression of sterol regulatory element-binding protein (SREBP)-1c. In conclusion, we clarified for the first time that triterpene alcohols and sterols from rice bran prevented diet-induced obesity by increasing fatty acid oxidation in muscles and decreasing fatty acid synthesis in the liver through GIP-dependent and GIP-independent mechanisms.


2012 ◽  
Vol 78 (24) ◽  
pp. 8611-8622 ◽  
Author(s):  
Lin Zhang ◽  
Tracey A. Veres-Schalnat ◽  
Arpad Somogyi ◽  
Jeanne E. Pemberton ◽  
Raina M. Maier

ABSTRACTRhamnolipids have multiple potential applications as “green” surfactants for industry, remediation, and medicine. As a result, they have been intensively investigated to add to our understanding of their biosynthesis and improve yields. Several studies have noted that the addition of a fatty acid cosubstrate increases rhamnolipid yields, but a metabolic explanation has not been offered, partly because biosynthesis studies to date have used sugar or sugar derivatives as the carbon source. The objective of this study was to investigate the role of fatty acid cosubstrates in improving rhamnolipid biosynthesis. A combination of stable isotope tracing and gene expression assays was used to identify lipid precursors and potential lipid metabolic pathways used in rhamnolipid synthesis when fatty acid cosubstrates are present. To this end, we compared the rhamnolipids produced and their yields using either glucose alone or glucose and octadecanoic acid-d35as cosubstrates. Using a combination of sugar and fatty acids, the rhamnolipid yield was significantly higher (i.e., doubled) than when glucose was used alone. Two patterns of deuterium incorporation (either 1 or 15 deuterium atoms) in a single Rha-C10lipid chain were observed for octadecanoic acid-d35treatment, indicating that in the presence of a fatty acid cosubstrate, bothde novofatty acid synthesis and β-oxidation are used to provide lipid precursors for rhamnolipids. Gene expression assays showed a 200- to 600-fold increase in the expression ofrhlAandrhlBrhamnolipid biosynthesis genes and a more modest increase of 3- to 4-fold of thefadAβ-oxidation pathway gene when octadecanoic acid was present. Taken together, these results suggest that the simultaneous use ofde novofatty acid synthesis and β-oxidation pathways allows for higher production of lipid precursors, resulting in increased rhamnolipid yields.


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