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Increasing Ethanol Tolerance in Industrially Important Ethanol Fermenting Organisms
Published in Ayerim Y. Hernández Almanza, Nagamani Balagurusamy, Héctor Ruiz Leza, Cristóbal N. Aguilar, Bioethanol, 2023
Kalyanasundaram Geetha Thanuja, Subburamu Karthikeyan
The genome of six isolates with n-butanol tolerance was re-sequenced and the mutations in the coding sequence of Clo1313_0853 and Clo1313_1798 were studied [5]. The gene Clo1313_0853 catalyzes the hydrolysis of phosphatidylcholine and phospholipids to produce phosphatidic acid (PA). The mutation in the gene truncates the protein by frameshift and protects the membrane in the presence of n-butanol/ethanol. Mutation in the gene Clo1313_1798, encoding alcohol dehydrogenase (adhE) increases its ability to use NADPH as a co-factor yielding increased ethanol and titer. The increased NADPH activities are associated with AdhE mutant, where the reverse flux through ADH reaction affects NADH/NAD+ ratio and the NADPH/NADP+ ratio. Deletion of adhE strain (LL1111) increases tolerance and inhibits several primary alcohols by reverse flux through AdhE [68].
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
The initiation of synthesis of all glycerolipids includes acylation of sn-glycerol-3-phosphate (G-3-P) to lysophosphatidic acid which is catalyzed by sn-1 glycerol-3-phosphate acyltransferase (GPAT). The frequent participation of acyl-CoA in comparison to any other substrate in this step leads to an asymmetric distribution of saturated and unsaturated fatty acids in different positions of phospholipids and TAGs. Further elongation of the acyl chains occurs in ER (Fig. 3.1). The role of GPAT in glycerolipid synthesis is still a topic of discussion as it is seen that the in yeast, one of the isoforms, SCT1, when overexpressed, enhances TAG accumulation while the other isoform, GPT1 decreases the accumulation. The homologs of GPAT in plants such as Arabidopsis have also been studied. It is seen that mutation in these genes does not affect the oil metabolism. However, it has been known that GPAT4 and GPAT6 participate in other functions such as generation of monoacylglycerol which ultimately leads to the cutin biosynthesis (Zheng et al., 2003). The next step is catalyzed by an enzyme called lysophosphatidic acid acyltransferase enzyme (LPAAT) which converts lysophosphatidic acid to phosphatidic acid. It is believed that LPAAT favors different types of fatty acyl-CoAs in different type of plants. LPAAT enzyme in Tropaeolaceae and Limnanthaceae family prefer very long fatty acyl-CoAs; similarly, medium-length fatty acyl-CoAs are preferred by this enzyme in plants such as coconut and palm. The third step in this pathway is the formation of diacylglycerol (DAG) from phosphatidic acid (Maisonneuve et al., 2010). The enzyme involved here is known as phosphatidate phosphatase1 (PAP1), which dephosphorylates phosphatidic acid. The final step in the biosynthesis of TAG is catalyzed by an enzyme called diacylglycerol acyltransferase (DGAT) which converts DAG to TAG (Weselake et al., AOCS lipid library).
Advancing Phospholipase D Enzymes as Diverse Drug Targets
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2020
Hortênsia Gomes Leala, Kimberly A. Stieglitzb
Although scPLD is not a member of PLD superfamily, it has been used to replace HKD-PLDs in order to elicit physiological effects caused by PA, which is also released through these enzymes catalytic activity. PA is a central phospholipid second messenger involved in many intracellular processes, and important intermediate in lipid biosynthesis (Kooijman et al., 2005). Altered PA signaling has been identified in various humans diseases, including cancers and neurodegenerative disorders (Foster and Xu, 2003; Oliveira and Di Paolo, 2010). In addition, scPLD presents a homology relation to the Bacillus subtilis PhoD alkaline phosphatase amino acid sequence (Zambonelli and Roberts, 2005). Phosphatases are found in the genome of Corynebacterineae, Propionibacterineae, Mycobacterium sp., Nocardia sp., Streptomyces sp., and Leishmania (Zambonelli and Roberts, 2005; Djakpa et al., 2016). Recently, a study involving docking, and a library screening of molecules used scPLD as a target to identified five derivatives based on the 4-aminopyrazolopyrimidine that presented inhibitory effects against this enzyme with IC50 values of 125, 25, 65, 20, and 12 nM for compounds 1,3,4,5,13, and 115, respectively (Djakpa et al., 2016). The authors also performed molecular docking analysis and high-throughput kinetic assay to verify the potential of inhibition of the compounds against selected phosphatases from human (PAP-HU1 and PAP-HU2) and acid phosphatase from Leishmania (PTP-LM). Kinetic analysis showed that PTP-LM exhibited the best inhibition with compounds 13 and 15 with a Kļ of 0.850 and 0.625 mM, respectively. The human PAP-HU1 and PAP-HU2 were best inhibited by compounds 3 and 4 with Ki ranging from 0.075 to 0.950 mM for inhibitor 3, and from 0.150 to 0.780 mM for inhibitor 4. In this scenario, scPLD structural information has been pointed to yield the possibility of developing anticancer drugs and drugs for infectious diseases.
The enigma of environmental organoarsenicals: Insights and implications
Published in Critical Reviews in Environmental Science and Technology, 2022
Xi-Mei Xue, Chan Xiong, Masafumi Yoshinaga, Barry Rosen, Yong-Guan Zhu
The biosynthesis of AsSugPLs is predicted to start from Oxo-Gly with or without the formation of the intermediate Oxo-PO4 (Fig. 1F) (Zhu et al., 2017b). Diacylglycerol and cytidine diphosphate-diacylglycerol derived from phosphatidic acid serve as intermediates in the membrane phospholipid biosynthesis. Diacylglycerol is converted into phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylthreonine, whereas cytidine diphosphate-diacylglycerol is a precursor for phosphatidylglycerol, phosphatidylinositol, cardiolipin, and phosphatidylserine in the prokaryotes (Jennings & Epand, 2020). However, whether AsSugPLs are synthesized from either Oxo-Gly and cytidine diphosphate-diacylglycerol or Oxo-PO4 and diacylglycerol is not clear yet. In addition, the biosynthesis of AsSugPLs likely takes place at the outer surface of the cytoplasmic membrane, similar to lipid biosynthesis.
The effects of phosphatidic acid on performance and body composition - a scoping review
Published in Journal of Sports Sciences, 2022
Filipe J. Teixeira, Nelson Tavares, Catarina N. Matias, Stuart M. Phillips
Phospholipid supplements have been gaining prominence due to their possible effect on sports performance (Jager et al., 2007). Phosphatidic acid (PA) is a structural phospholipid of cell membranes and an intracellular messenger that regulates several signalling proteins (Lim et al., 2003). Phospholipids contain two fatty acids and a phosphate group linked by a covalent bond to a glycerol molecule (Lim et al., 2003). Several studies have indicated that PA may be a signalling molecule that stimulates activation of the mechanistic target of rapamycin complex-1 (mTORC1) (Goodman, 2019; You et al., 2012, 2014). Stimulation of mTORC1 increases protein synthesis in response to RE (Dickinson et al., 2011). One could hypothesize that enhancing mTORC1 activity by the performance of RE and ingestion of PA may lead to a greater increase in muscle protein synthesis (MPS), which may lead to greater hypertrophic adaptations versus RE training without supplementation, especially if maintained at long term (> 10 weeks) (Damas et al., 2016). How PA activates mTORC1 and increases MPS is not yet fully understood.
Longitudinal metabolic alterations in plasma of rats exposed to low doses of high linear energy transfer radiation
Published in Journal of Environmental Science and Health, Part C, 2021
Tixieanna Dissmore, Andrew G DeMarco, Meth Jayatilake, Michael Girgis, Shivani Bansal, Yaoxiang Li, Khyati Mehta, Vijayalakshmi Sridharan, Kirandeep Gill, Sunil Bansal, John B Tyburski, Amrita K Cheema
Complex cellular responses triggered by exposure to non-lethal doses of ionizing radiation may lead to changes in metabolomic profiles depending on radiation type and dose.18–22 In this study, we report the results from a rat model aimed at delineating longitudinal alterations in the plasma metabolome after exposure to 0.5 Gy of 1H (250 MeV) or 16O (600 MeV/n) radiation. The dysregulated metabolites included certain classes of lipids such as phosphatidylethanolamine (PE), ceramide, sphingomyelin (SM) and lysophosphatidic acid (LPA). Pro-inflammatory cytokines and oxidative stress may stimulate the generation of SMs, from the ceramide response to sphingomyelin synthase in the Golgi apparatus.23 Dysregulation observed in SM(24:1) at the 3-month time point may indicate some degree of neuronal damage.24 Additionally, we found a significant increase in eicosapentaenoyl PAF C-16 after exposure to 0.5 Gy of 1H at 12 the month time point, which may be because of ionizing radiation-mediated oxidation of phospholipids. Radiation-induced peroxidation of fatty acids may indicate cellular damage at various levels.25,26 Lastly, we observed decreased levels of LPA(18:0) after exposure to 1H and 16O at 12 months. Previously it has been reported that inflammatory prostaglandins Phosphatidylcholine (PC) generates lysophosphatidylcholine (LPC) and lysophosphatidic acid (LPA) through the actions of Pla2) and phospholipase D (Pld) that is further converted to Phosphatidic acid (PA). Decreased levels of LPA may suggest increased levels of PA that can directly stimulate G protein-coupled receptor activation of mTor through resulting in increased cell proliferation.27