scholarly journals Acetate represents a major product of heptanoate and octanoate β-oxidation in hepatocytes isolated from neonatal piglets

1996 ◽  
Vol 318 (1) ◽  
pp. 235-240 ◽  
Author(s):  
Xi LIN ◽  
Sean H. ADAMS ◽  
Jack ODLE

An experiment was conducted to explore the nature of the radiolabel distribution in acid-soluble products (ASPs) resulting from the oxidation of [1-14C]C7:0 or C8:0 by isolated piglet hepatocytes. The differences between odd and even chain-length and the impacts of valproate and malonate upon the rate of β-oxidation and ASP characteristics were tested. A minor amount of fatty acid carboxyl carbon (⩽ 10% of organic acids identified by radio-HPLC) accumulated in ketone bodies regardless of chain-length or inhibitor used. In all cases, acetate represented the major reservoir of carboxyl carbon, accounting for 60–70% of radiolabel in identified organic acids. Cells given [1-14C]C7:0 accumulated 85% more carboxyl carbon in Krebs cycle intermediates when compared with C8:0, while accumulation in acetate was unaffected. The results are consistent with the hypothesis that anaplerosis from odd-carbon fatty acids affects the oxidative fate of fatty acid carbon. The piglet appears unique in that non-ketogenic routes of fatty acid carbon flow (i.e. acetogenesis) predominate in the liver of this species.

2011 ◽  
Vol 78 (2) ◽  
pp. 519-527 ◽  
Author(s):  
Qin Wang ◽  
Ryan C. Tappel ◽  
Chengjun Zhu ◽  
Christopher T. Nomura

ABSTRACTPseudomonas putidaKT2440 is capable of producing medium-chain-length polyhydroxyalkanoates (MCL-PHAs) when grown on unrelated carbon sources during nutrient limitation. Transcription levels of genes putatively involved in PHA biosynthesis were assessed by quantitative real-time PCR (qRT-PCR) inP. putidagrown on glycerol as a sole carbon source. The results showed that two genes,phaGand the PP0763 gene, were highly upregulated among genes potentially involved in the biosynthesis of MCL-PHAs from unrelated carbon sources. Previous studies have describedphaGas a 3-hydroxyacyl-acyl carrier protein (ACP)-coenzyme A (CoA) transferase, and based on homology, the PP0763 gene was predicted to encode a medium-chain-fatty-acid CoA ligase. High expression levels of these genes during PHA production inP. putidaled to the hypothesis that these two genes are involved in PHA biosynthesis from non-fatty acid carbon sources, such as glucose and glycerol. ThephaGppand PP0763 genes fromP. putidawere cloned and coexpressed with the engineeredPseudomonassp. 61-3 PHA synthase genephaCl(STQK)psin recombinantEscherichia coli. Up to 400 mg liter−1MCL-PHAs was successfully produced from glucose. This study has produced the largest amount of MCL-PHAs reported from non-fatty acid carbon sources in recombinantE. colito date and opens up the possibility of using inexpensive feedstocks to produce MCL-PHA polymers.


2001 ◽  
Vol 120 (5) ◽  
pp. A710-A710
Author(s):  
S LAL ◽  
J MCLAUGHLIN ◽  
O NIAZ ◽  
G DOCKRAY ◽  
A VARRO ◽  
...  

LWT ◽  
2021 ◽  
pp. 110867
Author(s):  
Min Hyeock Lee ◽  
Ha Ram Kim ◽  
Woo Su Lim ◽  
Min-Cheol Kang ◽  
Hee-Don Choi ◽  
...  

1964 ◽  
Vol 239 (5) ◽  
pp. 1305-1309
Author(s):  
J. Madsen ◽  
S. Abraham ◽  
I.L. Chaikoff
Keyword(s):  

Langmuir ◽  
2003 ◽  
Vol 19 (26) ◽  
pp. 10808-10815 ◽  
Author(s):  
Vincent Dupres ◽  
Sophie Cantin ◽  
Fewzi Benhabib ◽  
Françoise Perrot ◽  
Philippe Fontaine ◽  
...  
Keyword(s):  

2006 ◽  
Vol 72 (1) ◽  
pp. 536-543 ◽  
Author(s):  
Bo Zhang ◽  
Ross Carlson ◽  
Friedrich Srienc

ABSTRACT Polyhydroxyalkanoates (PHAs) have received considerable interest as renewable-resource-based, biodegradable, and biocompatible plastics with a wide range of potential applications. We have engineered the synthesis of PHA polymers composed of monomers ranging from 4 to 14 carbon atoms in either the cytosol or the peroxisome of Saccharomyces cerevisiae by harnessing intermediates of fatty acid metabolism. Cytosolic PHA production was supported by establishing in the cytosol critical β-oxidation chemistries which are found natively in peroxisomes. This platform was utilized to supply medium-chain (C6 to C14) PHA precursors from both fatty acid degradation and synthesis to a cytosolically expressed medium-chain-length (mcl) polymerase from Pseudomonas oleovorans. Synthesis of short-chain-length PHAs (scl-PHAs) was established in the peroxisome of a wild-type yeast strain by targeting the Ralstonia eutropha scl polymerase to the peroxisome. This strain, harboring a peroxisomally targeted scl-PHA synthase, accumulated PHA up to approximately 7% of its cell dry weight. These results indicate (i) that S. cerevisiae expressing a cytosolic mcl-PHA polymerase or a peroxisomal scl-PHA synthase can use the 3-hydroxyacyl coenzyme A intermediates from fatty acid metabolism to synthesize PHAs and (ii) that fatty acid degradation is also possible in the cytosol as β-oxidation might not be confined only to the peroxisomes. Polymers of even-numbered, odd-numbered, or a combination of even- and odd-numbered monomers can be controlled by feeding the appropriate substrates. This ability should permit the rational design and synthesis of polymers with desired material properties.


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