scholarly journals Engineering Fatty Acid Synthesis in Rhodosporidium Toruloides to Produce Mid-Chain Fatty Acids and Fatty Alcohols - CRADA 501

2021 ◽  
Author(s):  
Beth Hofstad
1993 ◽  
Vol 48 (7-8) ◽  
pp. 616-622 ◽  
Author(s):  
Jochen Fuhrmann ◽  
Klaus-Peter Heise

Abstract The colorless embryos of Cuphea wrightii A. Gray accumulate capric (about 30%) and lauric acid (about 50%) in their storage lipids. Fractionation studies show that the capacities for the synthesis of these medium-chain fatty acids (MCFA) from [1-14C]acetate were strictly bound to intact plastids. These, in turn, obligately required the addition of ATP. ATP could partially be substituted by ADP. Reduction of the pyridine nucleotide pool, required for opti­mum MCFA formation within the plastids, was driven by glucose 6-phosphate. Under these conditions the plastids were capable of synthesizing MCFA like the intact tissue. The presence of CoA in the incubation medium induced acyl-CoA formation. The observed accumulation of unesterified capric and lauric acid in the absence of CoA suggests that acyl-ACP thioesterase activity is involved in the chain termination. Treatment with cerulenin led to an unexpectedly small reduction of total fatty acid synthesis while the chain elongation of capric acid was clearly inhibited. A similar accumulation of capric acid at the expense of longer chain fatty acids has been observed after replacing ATP by ADP. These findings implicate that even the condensing enzymes are involved in the control of chain ter­mination.


1972 ◽  
Vol 129 (4) ◽  
pp. 929-935 ◽  
Author(s):  
Isabel A. Forsyth ◽  
Christopher R. Strong ◽  
Raymond Dils

1. The rate of fatty acid synthesis by mammary explants from rabbits pregnant for 16 days or from rabbits pseudopregnant for 11 days was stimulated up to 15-fold by culturing for 2–4 days with prolactin. This treatment initiated the predominant synthesis of C8:0 and C10:0 fatty acids, which are characteristic of rabbit milk. 2. Inclusion of insulin in the culture medium increased the rate of synthesis of these medium-chain fatty acids. By contrast the inclusion of corticosterone led to the predominant synthesis of long-chain fatty acids. When explants were cultured for 2–4 days with insulin, corticosterone and prolactin, the rate of fatty acid synthesis increased up to 42-fold, but both medium- and long-chain fatty acids were synthesized. 3. These results show that the stimulus to mammary-gland lipogenesis and the initiation of synthesis of medium-chain fatty acids observed between days 16 and 23 of pregnancy in the rabbit can be simulated in vitro by prolactin alone. 4. When mammary explants from rabbits pregnant for 23 days were cultured for 2 days with insulin, corticosterone and prolactin, the rate of fatty acid synthesis increased fivefold, but there was a preferential synthesis of long-chain fatty acids. Culture with prolactin alone had little effect on the rate or pattern of fatty acids synthesized. 5. The results are compared with findings in vivo on the control of lipogenesis in the rabbit mammary gland, and are contrasted with the known effects of hormones in vitro on the mammary gland of the mid-pregnant mouse.


1958 ◽  
Vol 149 (936) ◽  
pp. 414-420

1. Introduction: The role of acetate in fatty-acid synthesis In 1945 Folley and his colleagues (see Foiley 1949, 1952; Malpress 1946) suggested that, in the ruminant, short-chain fatty acids might be synthesized by the lactating mammary gland from acetate. These short-chain fatty acids might then serve as precursors for the synthesis of long-chain acids. Folley & French (1949, 1950) showed that in vitro slices of lactating ruminant mammary gland were able to synthesize fat from acetate, as indicated by a respiratory quotient greater than unity. Non-ruminant lactating mammary tissue was unable to do so, but could utilize glucose for fat synthesis. It was later shown, with the aid of tracers (Balmain, Folley & Glascock 1954) that non-ruminant lactating mammary gland slices could use acetate for the synthesis of fat, provided that glucose was also added. Experiments in vivo laid emphasis upon the synthesis of short-chain fatty acids by the mammary gland. Popják & Beeckmans (1950) showed that injection of [ carboxy - 14 C]acetate into the pregnant rabbit gave rise to a high degree of labelling in the mammary gland fat. Fractionation of these fatty acids (Popják, Folley & French 1950) showed that the label was predominantly concentrated in the short-chain fatty acids, and that this labelling was far higher than that found in the liver fatty acids, indicating synthesis in the gland itself.


1972 ◽  
Vol 128 (5) ◽  
pp. 1057-1067 ◽  
Author(s):  
E. D Saggerson

1. 0.5mm-Palmitate stimulated incorporation of [U-14C]glucose into glyceride glycerol and fatty acids in normal fat cells in a manner dependent upon the glucose concentration. 2. In the presence of insulin the incorporation of 5mm-glucose into glyceride fatty acids was increased by concentrations of palmitate, adrenaline and 6-N-2′-O-dibutyryladenosine 3′:5′-cyclic monophosphate up to 0.5mm, 0.5μm and 0.5mm respectively. Higher concentrations of these agents produced progressive decreases in the rate of glucose incorporation into fatty acids. 3. The effects of palmitate and lipolytic agents upon the measured parameters of glucose utilization were similar, suggesting that the effects of lipolytic agents are mediated through increased concentrations of free fatty acids. 4. In fat cells from 24h-starved rats, maximal stimulation of glucose incorporation into fatty acids was achieved with 0.25mm-palmitate. Higher concentrations of palmitate were inhibitory. In fat cells from 72h-starved rats, palmitate only stimulated glucose incorporation into fatty acids at high concentrations of palmitate (1mm and above). 5. The ability of fat cells to incorporate glucose into glyceride glycerol in the presence of palmitate decreased with increasing periods of starvation. 6. It is suggested that low concentrations of free fatty acids stimulate fatty acid synthesis from glucose by increasing the utilization of ATP and cytoplasmic NADH for esterification of these free fatty acids. When esterification of free fatty acids does not keep pace with their provision, inhibition of fatty acid synthesis occurs. Provision of free fatty acids far in excess of the esterification capacity of the cells leads to uncoupling of oxidative phosphorylation and a secondary stimulation of fatty acid synthesis from glucose.


1974 ◽  
Vol 142 (3) ◽  
pp. 611-618 ◽  
Author(s):  
D. Michael W. Salmon ◽  
Neil L. Bowen ◽  
Douglas A. Hems

1. Fatty acid synthesis de novo was measured in the perfused liver of fed mice. 2. The total rate, measured by the incorporation into fatty acid of3H from3H2O (1–7μmol of fatty acid/h per g of fresh liver), resembled the rate found in the liver of intact mice. 3. Perfusions with l-[U-14C]lactic acid and [U-14C]glucose showed that circulating glucose at concentrations less than about 17mm was not a major carbon source for newly synthesized fatty acid, whereas lactate (10mm) markedly stimulated fatty acid synthesis, and contributed extensive carbon to lipogenesis. 4. The identification of 50% of the carbon converted into newly synthesized fatty acid lends further credibility to the use of3H2O to measure hepatic fatty acid synthesis. 5. The total rate of fatty acid synthesis, and the contribution of glucose carbon to lipogenesis, were directly proportional to the initial hepatic glycogen concentration. 6. The proportion of total newly synthesized lipid that was released into the perfusion medium was 12–16%. 7. The major products of lipogenesis were saturated fatty acids in triglyceride and phospholipid. 8. The rate of cholesterol synthesis, also measured with3H2O, expressed as acetyl residues consumed, was about one-fourth of the basal rate of fatty acid synthesis. 9. These results are discussed in terms of the carbon sources of hepatic newly synthesized fatty acids, and the effect of glucose, glycogen and lactate in stimulating lipogenesis, independently of their role as precursors.


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