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Perfluorooctane Sulfonate (PFOS)
Published in Mark S. Johnson, Michael J. Quinn, Marc A. Williams, Allison M. Narizzano, Understanding Risk to Wildlife from Exposures to Per- and Polyfluorinated Alkyl Substances (PFAS), 2021
Other groups showed that PFOS primarily accounted for dampened mitochondrial β-oxidation activity as monitored on day 14 (Wan et al. 2012). Whereas total and peroxisomal β-oxidation were slightly, but increased (P < 0.01) at a dose of 10 mg/kg-d, mitochondrial β-oxidation was markedly decreased (P < 0.05 or P < 0.01) in all of the PFOS dose groups. Additionally, peroxisomal acyl-CoA oxidase, CYP 4A14, and acyl-CoA dehydrogenase mRNA transcripts were increased in the 5 and 10 mg/kg-d dose groups, observations that suggested degradation of long-chain fatty acids by peroxisomes. Increases in peroxisomal oxidation, in the absence of increased mitochondrial β-oxidation, has the potential to promote the accumulation of fatty acids in the liver (i.e., steatosis).
Synthesis of Antioxidants via Biocatalysis
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Free radicals are generated inside the cells through different pathways as discussed earlier. They cause serious cell injuries. Metal ions, such as iron, catalyze the production of even more free radicals, leading to more cell injuries. Phagocytes are the well-established sources of free radicals. Activated phagocytes are vigorously involved in oxidative burst. The mitochondrial electron transport system is another major source of ROS. This involves the NADH-coenzyme Q, succinate-coenzyme Q, and coenzyme QH2-cytochrome c reductases. The production of ROS by mitochondria is directly linked with oxygen consumption. Oxidases such as, xanthine oxidase, dopamine-b-hydroxylase, urate oxidase, d-amino acid oxidase, and fatty acyl CoA oxidase are also considered to be involved in ROS production.
Tailoring Triacylglycerol Biosynthetic Pathway in Plants for Biofuel Production
Published in Arindam Kuila, Sustainable Biofuel and Biomass, 2019
Kshitija Sinha, Ranjeet Kaur, Rupam Kumar Bhunia
β-oxidation of fatty acid is the process of cleavage of fatty acid carbon units into acetyl-CoA moieties, and it occurs in glyoxysome (Bewley, 2001). The glyoxysome contains the enzymes involved in this β-oxidation pathway, that is, acyl-CoA oxidase (ACX), multifunctional protein (MFP), and 3-ketoacyl-CoA thiolase (KAT). These enzymes catalyze oxidation, hydration and dehydrogenation, and thiolytic cleavage reactions, respectively (Graham, 2008). Other reactions are also involved which are required for the breakdown of unsaturated fatty acids with double or triple bonds in the cis configuration at even- and odd-numbered carbons in the chain. The enzymatic activity of ACX leads to the production of hydrogen peroxide which is a kind of reactive oxygen species and is necessary to be detoxified. This detoxification happens with the help of a catalase enzyme located inside the peroxisome or by ascorbate peroxidase (APX) present on the membrane of peroxisomes (Pracharoenwattana, 2010). After the breakdown of the fatty acids via β-oxidation, the acetyl-coA undergoes a sequence of reactions, altogether called the glyoxylate cycle, in which succinate and oxaloacetate are formed. The enzymes involved in this cycle such as citrate synthase, aconitase, and malate dehydrogenase also participate in the citric acid cycle. However, two enzymes known as isocitrate lyase and malate synthase work only for the glyoxylate cycle in bypassing the steps of decarboxylation in the citric acid cycle (Beevers, 1980). These two enzymes generate malate and succinate, both of which are the citric acid cycle intermediates which can be converted to oxaloacetate. Out of the two molecules of oxaloacetate formed here, one can rejoin the glyoxylate cycle while the other participates in gluconeogenesis (Beevers, 1980).
Current research and perspectives on microalgae-derived biodiesel
Published in Biofuels, 2020
Kartik Singh, Deeksha Kaloni, Sakshi Gaur, Shipra Kushwaha, Garima Mathur
For industrialized production of algal feedstock, an ideal strain should be highly productive along with a high lipid accumulation efficiency, as these factors code for the quantity of biodiesel produced by any given microalgal culture. Most microalgal species do not produce high amounts of lipids in the log phase. However, when they come across a nitrogen-deficient environment, they slow down their rate of biomass production and start producing energy storage products such as lipids and starch [149]. However, it is observed that an increasing rate of lipid synthesis could result in cell division reduction. In this case, overexpression of genes controlling lipid synthesis may be very beneficial if they are controllable by an inducible promoter that can be activated once the cells in the culture have reached high densities and entered the stationary phase [150]. Another approach to increased lipid accumulation is to decrease lipid catabolism. Studies have shown that knocking out genes of some enzymes that are vital for lipid catabolism, e.g. acyl CoA oxidase and acyl CoA synthase, will aid in increasing lipid storage [151].
Identification and characterization of candidates involved in production of OMEGAs in microalgae: a gene mining and phylogenomic approach
Published in Preparative Biochemistry and Biotechnology, 2018
Vikas U. Kapase, Asha A. Nesamma, Pannaga P. Jutur
Phylogenetic tree enables us to understand evolutionary relationships among the predicted proteins.[39,52] We have performed phylogenomic analyses of all the proteins from diverse group of microalgal species involved in production of OMEGAs to evaluate their evolutionary patterns (Figure 5). The phylogenetic tree reveals that most of the putative candidate genes with similar functions and motif patterns were clustered together are remarkably well conserved within Viridiplantae lineage. Figure 5 demonstrates that putative candidate genes such as FAD2 (delta-12 desaturase), ECR (enoyl-CoA reductase), FAD2 (delta-12 desaturase), ACOT (acyl CoA thioesterase), ECH (enoyl-CoA hydratase), and ACAT (acetyl-CoA acyltransferase) with similar domains and motif patterns were remarkably well conserved. Exceptionally, the acyl CoA oxidase (ACX) and stearoyl-CoA desaturase (SCD) were clustered together in one clade indicating the presence of single conserved domain (Figure 5). Comparative phylogenomic analysis of putative OMEGA genes predicts cross-talk between the essential metabolic pathways followed by their evolutionary patterns showing the possibility of gene duplication and/or either loss during the speciation, thus assuming that the overall domain and motif architecture are well conserved among the microalgal lineages.
The role of oxidative stress in pulmonary function in bakers exposed to flour dust
Published in International Journal of Occupational Safety and Ergonomics, 2022
Vahid Gharibi, Mohammad Hossein Ebrahimi, Esmaeel Soleimani, Narges Khanjani, Anahita Fakherpour, Majid Bagheri Hosseinabadi
Epidemiologic reports have shown that asthma, conjunctivitis, rhinitis and skin reactions are the most important health effects of exposure to flour dust. Among these effects, baker’s asthma is the most severe and most frequently considered occupational allergy [4,5]. However, the mechanism of development of baker’s asthma is not yet fully understood. It has been reported that fungal α-amylase, thioredoxin, plant lipid transfer protein, serine proteinase inhibitor, thaumatin-like protein, acyl-CoA oxidase, fructose-bisphosphate aldolase, glycoprotein with peroxidase activity, triose-phosphate isomerase and prolamins are the most important factors associated with asthma in bakers and other people exposed to flour [6].