Three Different Methods of Inhibiting Lipolysis in Human Chyme in Vitro: Efficiency and Effect on Phase Distribution of Lipids

1990 ◽  
Vol 79 (4) ◽  
pp. 349-355 ◽  
Author(s):  
D. R. Fine ◽  
P. L. Zentler-Munro ◽  
T. C. Northfield
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Acid Production ◽  
Acid Treatment ◽  
Phase Distribution ◽  
Significant Inhibition ◽  
Separate Experiment ◽  
Fatty Acid Production ◽  
Micellar Phase

1. The efficiencies of three different methods of inhibiting fatty acid production in chyme have been evaluated. The effects of each method on the phase distribution of fatty acids after ultracentrifugation have been studied. 2. Chyme fatty acid concentrations were measured during a 4 h incubation (a) without an inhibitor, (b) after acid treatment, (c) after addition of p-bromophenyl-boronic acid and (d) after heating. 3. In a separate experiment, fresh chyme was incubated to allow equilibration of lipolysis. Aliquots were treated by each inactivation method and ultracentrifuged overnight to separate the phases. Total and micellar fatty acids and glycerides were measured. 4. In the first experiment, acid treatment completely inhibited fatty acid generation producing 4 h concentrations which were 93.4 ± 5.6% (mean ± sem) of initial values compared with 398.0 ± 54.0% (P < 0.05) for uninhibited samples. p-Bromophenylboronic acid and heating gave significant but incomplete inhibition (132.9 ± 6.6% and 166.1 ± 15.2% of initial concentrations, respectively). 5. Ultracentrifugation disclosed five phases in all except the acid-treated samples, which had four. Micellar phase fatty acid concentrations were significantly higher in the acid-treated than in the untreated samples (2.6 ± 0.7 versus 1.7 ± 0.5 mmol/l, P = 0.05), as were glyceride concentrations (1.5 ± 0.4 vs 0.6 ± 0.3 mmol/l, P = 0.05). 6. It was concluded that acid treatment was the most efficient inhibitor of fatty acid production, but it disrupted the phases. p-Bromophenylboronic acid gave significant inhibition without causing phase disruption and was therefore the most useful inhibitor overall.

scholarly journals In vitro ruminal fermentation and fatty acid production by various oil seeds

2018 ◽  
Vol 48 (3) ◽  
pp. 526 ◽  
Author(s):  
P Kubelková ◽  
D Jalč ◽  
F Jančík ◽  
P Homolka
Keyword(s):  
Fatty Acid ◽  
Acid Production ◽  
Ruminal Fermentation ◽  
Fatty Acid Production ◽  
Oil Seeds

Evaluation of feeding glycerol on free-fatty acid production and fermentation kinetics of mixed ruminal microbes in vitro

2010 ◽  
Vol 101 (21) ◽  
pp. 8469-8472 ◽  
Author(s):  
N.A. Krueger ◽  
R.C. Anderson ◽  
L.O. Tedeschi ◽  
T.R. Callaway ◽  
T.S. Edrington ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Acid Production ◽  
Fatty Acid Production ◽  
Fermentation Kinetics ◽  
Free Fatty Acid Production ◽  
Kinetics Of

scholarly journals A Futile Metabolic Cycle of Fatty Acyl-CoA Hydrolysis and Resynthesis in Corynebacterium glutamicum and Its Disruption Leading to Fatty Acid Production

2020 ◽  
Author(s):  
Masato Ikeda ◽  
Keisuke Takahashi ◽  
Tatsunori Ohtake ◽  
Ryosuke Imoto ◽  
Haruka Kawakami ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Corynebacterium Glutamicum ◽  
Candidate Genes ◽  
Outer Layer ◽  
Acid Production ◽  
Fatty Acyl ◽  
Fatty Acid Production ◽  
Mycolic Acids

Fatty acyl-CoA thioesterase (Tes) and acyl-CoA synthetase (FadD) catalyze opposing reactions between acyl-CoAs and free fatty acids. Within the genome of Corynebacterium glutamicum, several candidate genes for each enzyme are present, although their functions remain unknown. Modified expressions of the candidate genes in the fatty acid producer WTΔfasR led to identification of one tes gene (tesA) and two fadD genes (fadD5 and fadD15), which functioned positively and negatively in fatty acid production, respectively. Genetic analysis showed that fadD5 and fadD15 are responsible for utilization of exogenous fatty acids and that tesA plays a role in supplying fatty acids for synthesis of the outer layer components mycolic acids. Enzyme assays and expression analysis revealed that tesA, fadD5, and fadD15 were co-expressed to create a cyclic route between acyl-CoAs and fatty acids. When fadD5 or fadD15 was disrupted in wild-type C. glutamicum, both disruptants excreted fatty acids during growth. Double disruptions of them resulted in a synergistic increase in production. Additional disruption of tesA revealed a canceling effect on production. These results indicate that the FadDs normally shunt the surplus of TesA-generated fatty acids back to acyl-CoAs for lipid biosynthesis and that interception of this shunt provokes cells to overproduce fatty acids. When this strategy was applied to a fatty acid high-producer, the resulting fadDs-disrupted and tesA-amplified strain exhibited a 72% yield increase relative to its parent and produced fatty acids, which consisted mainly of oleic acid, palmitic acid, and stearic acid, on the gram scale per liter from 1% glucose. IMPORTANCE The industrial amino acid producer Corynebacterium glutamicum has currently evolved into a potential workhorse for fatty acid production. In this organism, we obtained evidence showing the presence of a unique mechanism of lipid homeostasis, namely, a formation of a futile cycle of acyl-CoA hydrolysis and resynthesis mediated by acyl-CoA thioesterase (Tes) and acyl-CoA synthetase (FadD), respectively. The biological role of the coupling of Tes and FadD would be to supply free fatty acids for synthesis of the outer layer components mycolic acids and to recycle their surplusage to acyl-CoAs for membrane lipid synthesis. We further demonstrated that engineering of the cycle in a fatty acid high-producer led to dramatically improved production, which provides a useful engineering strategy for fatty acid production in this industrially important microorganism.

scholarly journals Elucidation of carbon sources used for the biosynthesis of fatty acids and sterols in the trypanosomatid Leishmania mexicana

1999 ◽  
Vol 342 (2) ◽  
pp. 397-405 ◽  
Author(s):  
Michael L. GINGER ◽  
Michael L. CHANCE ◽  
L. John GOAD
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Amino Acid ◽  
Acid Production ◽  
Carbon Sources ◽  
Mevalonic Acid ◽  
Leishmania Mexicana ◽  
Fatty Acid Production ◽  
Quantitative Measurements ◽  
Major Sterol

Sterols are necessary for the growth of trypanosomatid protozoans; sterol biosynthesis is a potential target for the use and development of drugs to treat the diseases caused by these organisms. This study has used 14C-labelled substrates to investigate the carbon sources utilized by promastigotes and amastigotes of Leishmania mexicana for the production of sterol [mainly ergosta-5,7,24(241)-trien-3β-ol] and the fatty acid moieties of the triacylglycerol (TAG) and phospholipid (PL) of the organism. The isoprenoid precursor mevalonic acid (MVA) was incorporated into the sterols, and the sterol precursor squalene, by the promastigotes of L. mexicana. However, acetate (the precursor to MVA in most organisms) was a very poor substrate for sterol production but was readily incorporated into the fatty acids of TAG and PL. Other substrates (glucose, palmitic acid, alanine, serine and isoleucine), which are metabolized to acetyl-CoA, were also very poor precursors to sterol but were incorporated into TAG and PL and gave labelling patterns of the lipids similar to those of acetate. In contrast, the amino acid leucine was the only substrate to be incorporated efficiently into the squalene and sterol of L. mexicana promastigotes. Quantitative measurements revealed that at least 70-80% of the sterol synthesized by the promastigotes of L. mexicana is produced from carbon provided by leucine metabolism. Studies with the amastigote form of L. mexicana showed that in this case leucine was again the major sterol precursor, whereas acetate was utilized for fatty acid production.

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