scholarly journals Trophic upgrading and mobilization of wax esters in microzooplankton

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7549
Author(s):  
Keyana Roohani ◽  
Brad A. Haubrich ◽  
Kai-Lou Yue ◽  
Nigel D’Souza ◽  
Amanda Montalbano ◽  
...  
Keyword(s):  
Lipid Profile ◽  
Energy Demand ◽  
Model Organism ◽  
Fatty Alcohols ◽  
Wax Esters ◽  
Oxyrrhis Marina ◽  
Show Evidence ◽  
Saponifiable Fraction ◽  
Catabolic Response ◽  
Long Chain

Heterotrophic protists play pivotal roles in aquatic ecosystems by transferring matter and energy, including lipids, from primary producers to higher trophic predators. Using Oxyrrhis marina as a model organism, changes to the non-saponifiable protist lipids were investigated under satiation and starvation conditions. During active feeding on the alga Cryptomonas sp., the O. marina hexane soluble non-saponifiable fraction lipid profile reflected its food source with the observed presence of long chain mono-unsaturated fatty alcohols up to C25:1. Evidence of trophic upgrading in O. marina was observed with long chain mono-unsaturated fatty alcohol accumulation of up to C35:1. To the best of our knowledge, this is the first evidence that heterotrophic dinoflagellates are capable of producing ester derived alcohols and that dinoflagellates like O. marina are capable of synthesizing fatty alcohols up to C35. Additionally, we show evidence of trophic upgrading of lipids. During a 20-day resource deprivation, the lipid profile remained constant. During starvation, the mobilization of wax esters as energy stores was observed with long chain fatty alcohols mobilized first. Changes in lipid class profile and utilization of wax esters in O. marina provides insight into the types of lipids available for energy demand, the transfer of lipids through the base of marine food webs, and the catabolic response induced by resource deprivation.

scholarly journals Lipases of germinating jojoba seeds efficiently hydrolyze triacylglycerols and wax esters and display wax ester-synthesizing activity

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Adam Kawiński ◽  
Magdalena Miklaszewska ◽  
Szymon Stelter ◽  
Bartosz Głąb ◽  
Antoni Banaś
Keyword(s):  
Fatty Acids ◽  
Monounsaturated Fatty Acids ◽  
Fatty Alcohols ◽  
Wax Esters ◽  
In Vitro Assays ◽  
Wax Ester ◽  
Glucose Content ◽  
Esterification Reactions ◽  
Long Chain

Abstract Background Simmondsia chinensis (jojoba) is the only plant known to store wax esters instead of triacylglycerols in its seeds. Wax esters are composed of very-long-chain monounsaturated fatty acids and fatty alcohols and constitute up to 60% of the jojoba seed weight. During jojoba germination, the first step of wax ester mobilization is catalyzed by lipases. To date, none of the jojoba lipase-encoding genes have been cloned and characterized. In this study, we monitored mobilization of storage reserves during germination of jojoba seeds and performed detailed characterization of the jojoba lipases using microsomal fractions isolated from germinating seeds. Results During 26 days of germination, we observed a 60–70% decrease in wax ester content in the seeds, which was accompanied by the reduction of oleosin amounts and increase in glucose content. The activity of jojoba lipases in the seed microsomal fractions increased in the first 50 days of germination. The enzymes showed higher activity towards triacylglycerols than towards wax esters. The maximum lipase activity was observed at 60 °C and pH around 7 for triacylglycerols and 6.5–8 for wax esters. The enzyme efficiently hydrolyzed various wax esters containing saturated and unsaturated acyl and alcohol moieties. We also demonstrated that jojoba lipases possess wax ester-synthesizing activity when free fatty alcohols and different acyl donors, including triacylglycerols and free fatty acids, are used as substrates. For esterification reactions, the enzyme utilized both saturated and unsaturated fatty alcohols, with the preference towards long chain and very long chain compounds. Conclusions In in vitro assays, jojoba lipases catalyzed hydrolysis of triacylglycerols and different wax esters in a broad range of temperatures. In addition, the enzymes had the ability to synthesize wax esters in the backward reaction. Our data suggest that jojoba lipases may be more similar to other plant lipases than previously assumed.

scholarly journals Identification of potential drug targets in Salmonella enterica sv. Typhimurium using metabolic modelling and experimental validation

Microbiology ◽  
2014 ◽  
Vol 160 (6) ◽  
pp. 1252-1266 ◽  
Author(s):  
Hassan B. Hartman ◽  
David A. Fell ◽  
Sergio Rossell ◽  
Peter Ruhdal Jensen ◽  
Martin J. Woodward ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Energy Demand ◽  
Drug Targets ◽  
Minimal Medium ◽  
Model Organism ◽  
Metabolic Model ◽  
Scale Model ◽  
Glucose Minimal Medium ◽  
A Genome ◽  
Genome Scale

Salmonella enterica sv. Typhimurium is an established model organism for Gram-negative, intracellular pathogens. Owing to the rapid spread of resistance to antibiotics among this group of pathogens, new approaches to identify suitable target proteins are required. Based on the genome sequence of S. Typhimurium and associated databases, a genome-scale metabolic model was constructed. Output was based on an experimental determination of the biomass of Salmonella when growing in glucose minimal medium. Linear programming was used to simulate variations in the energy demand while growing in glucose minimal medium. By grouping reactions with similar flux responses, a subnetwork of 34 reactions responding to this variation was identified (the catabolic core). This network was used to identify sets of one and two reactions that when removed from the genome-scale model interfered with energy and biomass generation. Eleven such sets were found to be essential for the production of biomass precursors. Experimental investigation of seven of these showed that knockouts of the associated genes resulted in attenuated growth for four pairs of reactions, whilst three single reactions were shown to be essential for growth.

Epicuticular Waxes from Leaves of Maple (Acer pseudoplatanus L.)

1990 ◽  
Vol 45 (6) ◽  
pp. 599-601 ◽  
Author(s):  
R. B. N. Prasad ◽  
Paul-Gerhard Gülz
Keyword(s):  
Fatty Acids ◽  
Wax Esters ◽  
Acer Pseudoplatanus ◽  
Long Chain Fatty Acids ◽  
Epicuticular Waxes ◽  
Primary Alcohols ◽  
Free Alcohol ◽  
Long Chain ◽  
Chain Fatty Acids

Abstract The epicuticular waxes from the leaves of maples (Acer pseudoplatanus L.) contained hydrocarbons (6.9%), wax esters (5.5%), aldehydes (38.1%), primary alcohols (10.2%) and fatty acids (17.1%). In addition to these common wax lipids, benzyl acyl esters (2.1%) and triterpenoids were also present. β-Sitosterol, β-amyrin and 24-methylene-cycloartenol were found in the form of acetates (14.4%). β-Amyrin was also present as free alcohol (4.9%) and esterified with long chain fatty acids (~ 0.7%).

scholarly journals The effect of a duodenal-jejunal bypass liner on lipid profile and blood concentrations of long chain polyunsaturated fatty acids

2020 ◽  
Author(s):  
Michael A. Glaysher ◽  
James Ward ◽  
Madhawi Aldhwayan ◽  
Aruchuna Ruban ◽  
Christina Gabriele Prechtl ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Lipid Profile ◽  
Blood Concentrations ◽  
Jejunal Bypass ◽  
Long Chain
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