scholarly journals Biosynthesis of Long Chain Alkyl Diols and Long Chain Alkenols in Nannochloropsis spp. (Eustigmatophyceae)

2019 ◽  
Vol 60 (8) ◽  
pp. 1666-1682
Author(s):  
Sergio Balzano ◽  
Laura Villanueva ◽  
Marijke de Bar ◽  
Diana X Sahonero Canavesi ◽  
Caglar Yildiz ◽  
...  

AbstractWe investigated potential biosynthetic pathways of long chain alkenols (LCAs), long chain alkyl diols (LCDs), and long chain hydroxy fatty acids (LCHFAs) in Nannochloropsis oceanica and Nannochloropsis gaditana, by combining culturing experiments with genomic and transcriptomic analyses. Incubation of Nannochloropsis spp. in the dark for 1 week led to significant increases in the cellular concentrations of LCAs and LCDs in both species. Consistently, 13C-labelled substrate experiments confirmed that both LCA and LCD were actively produced in the dark from C14–18 fatty acids by either condensation or elongation/hydroxylation, although no enzymatic evidence was found for the former pathway. Nannochloropsis spp. did, however, contain (i) multiple polyketide synthases (PKSs) including one type (PKS-Clade II) that might catalyze incomplete fatty acid elongations leading to the formation of 3-OH-fatty acids, (ii) 3-hydroxyacyl dehydratases (HADs), which can possibly form Δ2/Δ3 monounsaturated fatty acids, and (iii) fatty acid elongases (FAEs) that could elongate 3-OH-fatty acids and Δ2/Δ3 monounsaturated fatty acids to longer products. The enzymes responsible for reduction of the long chain fatty acids to LCDs and LCAs are, however, unclear. A putative wax ester synthase/acyl coenzyme A (acyl-CoA): diacylglycerol acyltransferase is likely to be involved in the esterification of LCAs and LCDs in the cell wall. Our data thus provide useful insights in predicting the biosynthetic pathways of LCAs and LCDs in phytoplankton suggesting a key role of FAE and PKS enzymes.

2021 ◽  
Vol 3 (Supplement_1) ◽  
pp. i19-i19
Author(s):  
Divya Ravi ◽  
Carmen del Genio ◽  
Haider Ghiasuddin ◽  
Arti Gaur

Abstract Glioblastomas (GBM) or Stage IV gliomas, are the most aggressive of primary brain tumors and are associated with high mortality and morbidity. Patients diagnosed with this lethal cancer have a dismal survival rate of 14 months and a 5-year survival rate of 5.6% despite a multimodal therapeutic approach, including surgery, radiation therapy, and chemotherapy. Aberrant lipid metabolism, particularly abnormally active de novo fatty acid synthesis, is recognized to have a key role in tumor progression and chemoresistance in cancers. Previous studies have reported a high expression of fatty acid synthase (FASN) in patient tumors, leading to multiple investigations of FASN inhibition as a treatment strategy. However, none of these have developed as efficacious therapies. Furthermore, when we profiled FASN expression using The Cancer Genome Atlas (TCGA) we determined that high FASN expression in GBM patients did not confer a worse prognosis (HR: 1.06; p-value: 0.51) and was not overexpressed in GBM tumors compared to normal brain. Therefore, we need to reexamine the role of exogenous fatty acid uptake over de novofatty acid synthesis as a potential mechanism for tumor progression. Our study aims to measure and compare fatty acid oxidation (FAO) of endogenous and exogenous fatty acids between GBM patients and healthy controls. Using TCGA, we have identified the overexpression of multiple enzymes involved in mediating the transfer and activation of long-chain fatty acids (LCFA) in GBM tumors compared to normal brain tissue. We are currently conducting metabolic flux studies to (1) assess the biokinetics of LCFA degradation and (2) establish exogenous versus endogenous LCFA preferences between patient-derived primary GBM cells and healthy glial and immune cells during steady state and glucose-deprivation.


2009 ◽  
Vol 4 (10) ◽  
pp. 1934578X0900401 ◽  
Author(s):  
Christel Brunschwig ◽  
François Xavier Collard ◽  
Jean-Pierre Bianchini ◽  
Phila Raharivelomanana

In order to establish a chemical fingerprint of vanilla diversity, thirty samples of V. planifolia J. W. Moore and V. tahitensis G. Jackson cured beans from seven producing countries were examined for their aroma and fatty acid contents. Both fatty acid and aroma compositions were found to vary between vanilla species and origins. Vanillin was found in higher amounts in V. planifolia (1.7-3.6% of dry matter) than in V. tahitensis (1.0-2.0%), and anisyl compounds were found in lower amounts in V. planifolia (0.05%) than in V. tahitensis (1.4%-2.1%). Ten common and long chain monounsaturated fatty acids (LCFA) were identified and were found to be characteristic of the vanilla origin. LCFA derived from secondary metabolites have discriminating compositions as they reach 5.9% and 15.8% of total fatty acids, respectively in V. tahitensis and V. planifolia. This study highlights the role of the curing method as vanilla cured beans of two different species cultivated in the same country were found to have quite similar fatty acid compositions.


2009 ◽  
Vol 296 (1) ◽  
pp. E211-E221 ◽  
Author(s):  
Stéphane Fourcade ◽  
Montserrat Ruiz ◽  
Carme Camps ◽  
Agatha Schlüter ◽  
Sander M. Houten ◽  
...  

Peroxisomes are essential organelles exerting key functions in fatty acid metabolism such as the degradation of very long-chain fatty acids (VLCFAs). VLCFAs accumulate in X-adrenoleukodystrophy (X-ALD), a disease caused by deficiency of the Abcd1 peroxisomal transporter. Its closest homologue, Abcd2, exhibits a high degree of functional redundancy on the catabolism of VLCFA, being able to prevent X-ALD-related neurodegeneration in the mouse. In the search for specific roles of Abcd2, we screened fatty acid profiles in organs and primary neurons of mutant knockout mice lacking Abcd2 in basal conditions and under dietary challenges. Our results indicate that ABCD2 plays a role in the degradation of long-chain saturated and ω9-monounsaturated fatty acids and in the synthesis of docosahexanoic acid (DHA). Also, we demonstrated a defective VLCFA β-oxidation ex vivo in brain slices of Abcd1 and Abcd2 knockouts, using radiolabeled hexacosanoic acid and the precursor of DHA as substrates. As DHA levels are inversely correlated with the incidence of Alzheimer's and several degenerative conditions, we suggest that ABCD2 may act as modulator/modifier gene and therapeutic target in rare and common human disorders.


2006 ◽  
Vol 72 (2) ◽  
pp. 1373-1379 ◽  
Author(s):  
Rainer Kalscheuer ◽  
Tim Stöveken ◽  
Heinrich Luftmann ◽  
Ursula Malkus ◽  
Rudolf Reichelt ◽  
...  

ABSTRACT Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant Escherichia coli strain by coexpression of a fatty alcohol-producing bifunctional acyl-coenzyme A reductase from the jojoba plant and a bacterial wax ester synthase from Acinetobacter baylyi strain ADP1, catalyzing the esterification of fatty alcohols and coenzyme A thioesters of fatty acids. In the presence of oleate, jojoba oil-like wax esters such as palmityl oleate, palmityl palmitoleate, and oleyl oleate were produced, amounting to up to ca. 1% of the cellular dry weight. In addition to wax esters, fatty acid butyl esters were unexpectedly observed in the presence of oleate. The latter could be attributed to solvent residues of 1-butanol present in the medium component, Bacto tryptone. Neutral lipids produced in recombinant E. coli were accumulated as intracytoplasmic inclusions, demonstrating that the formation and structural integrity of bacterial lipid bodies do not require specific structural proteins. This is the first report on substantial biosynthesis and accumulation of neutral lipids in E. coli, which might open new perspectives for the biotechnological production of cheap jojoba oil equivalents from inexpensive resources employing recombinant microorganisms.


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