Fatty-acid biosynthesis and acetyl-coa carboxylase as a target of diclofop, fenoxaprop and other aryloxy-phenoxy-propionic acid herbicides

1988 ◽  
Vol 43 (1-2) ◽  
pp. 47-54 ◽  
Author(s):  
Klaus Kobek ◽  
Manfred Focke ◽  
K. Lichtenthaler Botanisches
Keyword(s):  
Fatty Acid ◽  
Propionic Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Free Acid ◽  
Acetate Incorporation ◽  
Acetyl Coa Carboxylase ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Acid Herbicides

The effect of the herbicides and aryloxy-phenoxy-propionic acid derivatives diclofop, fenoxaprop, fluazifop and haloxyfop and their ethyl, methyl or butyl esters on the de novo fatty-acid biosynthesis of isolated chloroplasts was investigated with intact chloroplasts isolated from sensitive grasses (Poaceae) and tolerant dicotyledonous plants (Pisum, Spinacia). The 4 herbicides (free-acid form) block the de novo fatty-acid biosynthesis ([2-14C]acetate incorporation into the total fatty-acid fraction) of the sensitive Avena chloroplasts in a dose-dependent manner. The I50- values (a 50% inhibition of the [14C]acetate incorporation) lie in the range of 10-7 to 2 x 10-6 ᴍ. The ethyl or methyl esters (diclofop, fenoxaprop, haloxyfop) and butyl ester (fluazifop) do not affect the de novo fatty-acid biosynthesis of isolated chloroplasts or only at a very high concentration of ca. 10-4 ᴍ. In contrast, the de novo fatty-acid biosynthesis of the tolerant dicotyledonous species (pea, spinach) is not affected by the 4 aryloxy-phenoxy-propionic acid herbicides. In an enzyme preparation isolated from chloroplasts of the herbicide-sensitive barley plants the de novo fatty-acid biosynthesis from [14C]acetate and [14C]acetyl-CoA is blocked by all 4 herbicides (free acids), whereas that of [14C]malonate and [14C]malonyl-CoA is not affected. This strongly suggests that the target of all 4 herbicides (free-acid form) is the acetyl-CoA carboxylase within the chloroplasts. The applied ester derivatives, in turn, which are ineffective in the isolated chloroplast test system, have equally little or no effect on the activity of the acetyl-CoA carboxylase. It is assumed that the acetyl-CoA carboxylase of the tolerant dicot plants investigated is modified in such a way that the 4 herbicides cannot bind to and affect the target

Mode of Action of Herbicides Affecting Acetyl-CoA Carboxylase and Fatty Acid Biosynthesis

1990 ◽  
Vol 45 (5) ◽  
pp. 521-528 ◽  
Author(s):  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acid ◽  
Mode Of Action ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Acetyl Coa Carboxylase ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Enzyme Preparations ◽  
Acid Herbicides ◽  
Target Enzyme

The mode of action of cyclohexane-l,3-dione-type (cycloxydim, clethodim, sethoxydim, tralkoxydim) and aryloxyphenoxypropanoate-type herbicides (diclofop, fenoxaprop, haloxyfop, fluazifop) is summarized in this review. Both herbicide classes, though structurally completely different, specifically block the same target enzyme i.e. the plastid acetyl-CoA carboxylase (ACC) (EC 6.4.1.2). Most members of the Poaceae are sensitive towards both herbicide groups, whereas other monocotyledonous plants as well as the dicotyledonous plants appear to be resistant. This resistance, which can be found on the level of whole plants, in isolated chloroplasts and also on the level of ACC-enzyme preparations, is apparently due to a modification of the target enzyme ACC. Within the sensitive grass family some members (Festuca and Poa species) are partially tolerant against both graminicide groups. In the case of cyclohexanedione herbicides the tolerance seems to be due to a reduced sensitivity of the target enzyme. In the case of aryloxyphenoxypropionic acid herbicides the tolerance is apparently based on a combined action of cytoplasmic factors (metabolization?) and a slightly reduced sensitivity of the target enzyme. From differences in the sensitivity of certain grasses against the two herbicide classes it is concluded that both graminicide groups bind to the same binding domaine of the ACC enzyme but possess different subsites. The consequences of the block of de novo fatty acid biosynthesis in the plastids of sensitive plants is the lack of glycerolipid and biomembrane formation which finally causes cell death in the meristematic tissues.

Studies on the Inhibition of Biotin-Containing Carboxylases by Acetyl-CoA Carboxylase Inhibitors

1993 ◽  
Vol 48 (3-4) ◽  
pp. 294-300 ◽  
Author(s):  
Anja Motel ◽  
Simone Günther ◽  
Martin Clauss ◽  
Klaus Kobek ◽  
Manfred Focke ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Higher Plants ◽  
Acetate Incorporation ◽  
Acetyl Coa Carboxylase ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Malonyl Coa ◽  
Key Enzyme

In higher plants the biosynthetic machinery of de novo fatty acid biosynthesis, measured as [14C]acetate incorporation into fatty acids, is predominantly located in plastids. A key enzyme in this pathway is the biotin-containing acetyl-CoA carboxylase (ACC , EC 6.4.1.2) which catalyzes the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA. The ACC from Poaceae is very efficiently blocked by two herbicide classes, the cyclohexane-1,3-diones (e.g. sethoxydim, cycloxydim) and the aryloxyphenoxy-propionic acids (e.g. diclofop, fluazifop). It is shown that within the Poaceae not only different species but also different varieties exist which exhibit an altered sensitivity and tolerance towards both herbicide classes, which points to a mutation of the target enzyme ACC. In purifying the ACC we extended our research to the possible presence of other biotin-containing plant enzymes. In protein preparations from maize, oat, barley, pea and lentil we were able to demonstrate the carboxylation of acetyl-CoA, propionyl-CoA and methylcrotonyl-CoA. The two herbicide classes not only block the ACC, but also the activity of the propionyl-CoA carboxylase (PCC ), whereas the methylcrotonyl- CoA carboxylase (MCC ), a distinct biotin-containing enzyme from mitochondria, is not affected. MCC may play a role in isoprenoid catabolism. Whether PCC is a separate plastid enzyme or only a side activity of ACC is under current investigation. The efficiency of the graminicides in sensitive Poaceae is then not only determined by the inhibition of ACC, malonyl-CoA and fatty acid biosynthesis, but also by the exclusion of the PCC-catalyzed metabolic pathways of the plant cell.

Effect of Thiolactomycin on de novo Fatty Acid Biosynthesis in Plants

1990 ◽  
Vol 45 (5) ◽  
pp. 518-520 ◽  
Author(s):  
Manfred Focke ◽  
Andrea Feld ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Fatty Acid Synthetase ◽  
Acetate Incorporation ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Malonyl Coa ◽  
Total Fatty Acids

Thiolactomycin was shown to be a potent inhibitor of de novo fatty acid biosynthesis in intact isolated chloroplasts (measured as [14C]acetate incorporation into total fatty acids). In our attempt to further localize the inhibition site we confirmed the inhibition with a fatty acid synthetase preparation, measuring the incorporation of [14C]malonyl-CoA into total fatty acids. From the two proposed enzymic targets of the fatty acid synthetase by thiolactomycin we could exclude the acetyl-CoA: ACP transacetylase. It appears that the inhibition by thiolactomycin occurs on the level of the condensing enzymes, i.e. the 3-oxoacyl-ACP synthases. We also demonstrated that the two starting enzymes of de novo fatty acid biosynthesis, the acetyl-CoA synthetase and the acetyl-CoA carboxylase, are not affected by thiolactomycin.

Notes: Inhibition of the Acetyl-CoA Carboxylase of Barley Chloroplasts by Cycloxydim and Sethoxydim

1987 ◽  
Vol 42 (11-12) ◽  
pp. 1361-1363 ◽  
Author(s):  
Manfred Focke ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Enzyme Preparation ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Acetyl Coa Carboxylase ◽  
Acid Biosynthesis ◽  
Hordeum Vulgare L ◽  
Acetyl Coa ◽  
Malonyl Coa

The effect of the three cyclohexane-1,3-dione derivatives cycloxydim, sethoxydim and clethodim on the incorpora­tion of 14C-labelled acetate, malonate. acctyl-CoA or malonyl-CoA into fatty acids was studied in an enzyme preparation isolated from barley chloroplasts (Hordeum vulgare L. var. “Alexis”). The herbicides cycloxydim, clethodim and sethoxydim block the de novo fatty acid biosynthesis from [2-14C]acetatc and [1-14C]acetyl-CoA, whereas that of [2-14C]malonatc and [2-14C)malonyl-CoA is not affected. The data indicate that the mode of action of the cyclohexane-1,3-dione derivatives in the sensitive bar­ley plant consists in the inhibition of de novo fatty acid biosynthesis by blocking the acetyl-CoA carboxylase (EC 6.4.1.2.).

Lipid Biosynthesis Inhibitors

Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 435-449 ◽  
Author(s):  
John W. Gronwald
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Higher Plants ◽  
Lipid Biosynthesis ◽  
Chloroplast Envelope ◽  
Acetyl Coa Carboxylase ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Surface Lipids

Five classes of herbicides (carbamothioates, chloroacetamides, substituted pyridazinones, cyclohexanediones, and aryloxyphenoxypropionic acids) have been reported to inhibit lipid biosynthesis in higher plants. Carbamothioates impair the synthesis of surface lipids (waxes, cutin, suberin). These effects have been attributed to the ability of this herbicide class to inhibit one or more acyl-CoA elongases. Though as yet poorly characterized, these enzymes are associated with the endoplasmic reticulum and catalyze the condensation of malonyl-CoA with fatty acid acyl-CoA substrates to form very long-chain fatty acids used in the synthesis of surface lipids. There is contradictory evidence regarding the effects of chloroacetamide herbicides on de novo fatty acid biosynthesis. Selected substituted pyridazinones decrease the degree of unsaturation of plastidic galactolipids. This effect is attributed to the ability of selected members of this herbicide class to inhibit fatty acid desaturases which are thought to be located in the chloroplast envelope. Aryloxyphenoxypropionic acid and cyclohexanedione herbicides inhibit de novo fatty acid biosynthesis in grasses. The target site for these herbicide classes is the enzyme acetyl-CoA carboxylase which is found in the stroma of plastids. In most cases, selectivity between grasses and dicots is expressed at this site. Aryloxyphenoxypropionic acids and cyclohexanediones are reversible, linear, noncompetitive inhibitors of acetyl-CoA carboxylase from grasses. Both classes are also mutually exclusive inhibitors of grass acetyl-CoA carboxylase which suggests that they bind at a common domain on the enzyme.

Inhibition of de novo Fatty-Acid Biosynthesis in Isolated Chloroplasts by the Antibiotic Cerulenin and Its Synthetic Derivatives

1992 ◽  
Vol 47 (5-6) ◽  
pp. 382-386 ◽  
Author(s):  
Bernd List ◽  
Andrea Golz ◽  
Wilhelm Boland ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acid ◽  
Inhibitory Activity ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Specific Inhibitor ◽  
Hydrocarbon Chain ◽  
Acetate Incorporation ◽  
Acid Biosynthesis ◽  
Structural Element ◽  
Isolated Chloroplasts

The antibiotic cerulenin was shown to be a potent dose-dependent inhibitor of de novo fattyacid biosynthesis in intact isolated chloroplasts of different plants (measured as [14C]acetate incorporation into the total fatty-acid fraction). Various chemical derivatives of cerulenin were synthesized and tested in the chloroplast assay-system of oat, spinach and pea. Modifications of the hydrocarbon chain of cerulenin (e.g. tetrahydro-cerulenin and its short-chain cis-2,3-epoxy-4-oxoheptanamide derivative) decreased the inhibitory activity of cerulenin, whereas variations of the epoxy-oxo-amide structural element led to a complete loss of inhibition potency. The results indicate that the naturally occurring antibiotic cerulenin is the most active specific inhibitor of de novo fatty-acid biosynthesis, but the formation of the hydroxylactam ring seems to be an essential requirement for the inhibitory activity. Those structural analogues of cerulenin, which can no longer form a hydroxylactam ring, do not possess any inhibitory capacity.

Inhibition Of Plant Acetyl-Co A Synthetase By Alkyl-Adenylates

1992 ◽  
Vol 47 (11-12) ◽  
pp. 845-850 ◽  
Author(s):  
Andrea Golz ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Inhibition Mechanism ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Enzymic Reaction ◽  
Inhibition Constants

The plant acetyl-CoA synthetase (ACS) is bound to the plastids and provides acetyl-CoA, the starting substrate for de novo fatty acid biosynthesis in plastids. This enzymic reaction, which consumes ATP and releases AMP, can be inhibited by different alkyladenylates such as ethyl-, isopropyl-, propyl- or allyl-adenylates as is shown here. The inhibition mechanism is competitive with respect to ATP and non-com petitive with respect to acetate. I50-values and the inhibition constants K( (ATP), Ki (acetate) and Kii (acetate) are given. The results suggest that, also in plants, acetyl-adenylate is the endogenous intermediate in the enzymic formation of acetyl-CoA from acetate by acetyl-CoA synthetase

Glucocorticoid regulation of fatty acid synthase gene expression in fetal rat lung

1993 ◽  
Vol 265 (2) ◽  
pp. L140-L147 ◽  
Author(s):  
Z. X. Xu ◽  
W. Stenzel ◽  
S. M. Sasic ◽  
D. A. Smart ◽  
S. A. Rooney
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Fatty Acid Biosynthesis ◽  
Fetal Lung ◽  
Acetyl Coa Carboxylase ◽  
Rat Lung ◽  
Acid Biosynthesis ◽  
Atp Citrate Lyase ◽  
Acetyl Coa ◽  
Citrate Lyase

There are developmental and glucocorticoid-induced increases in the rate of fatty acid biosynthesis and in the activity of fatty acid synthase in late gestation fetal lung. We have now measured mRNA levels of fatty acid synthase and of two other enzymes of fatty acid biosynthesis, ATP citrate lyase and acetyl-CoA carboxylase, in developing fetal and postnatal rat lung and in fetal lung explants cultured with and without dexamethasone. There was a developmental increase in the mRNA for fatty acid synthase with the maximum level being reached on fetal day 21 (term is fetal day 22). This profile was similar to that reported for de novo fatty acid synthesis and fatty acid synthase activity. There was a similar but less pronounced developmental increase in the mRNA for ATP citrate lyase and a corresponding increase in its activity. There was no developmental change in the mRNA for acetyl-CoA carboxylase. Dexamethasone increased the level of fatty acid synthase mRNA approximately threefold but had no effect on those for ATP citrate lyase and acetyl-CoA carboxylase. The effect of dexamethasone on fatty acid synthase mRNA was rapid, biphasic, and partly inhibited by actinomycin D and cycloheximide. We conclude that glucocorticoids increase expression of the gene for fatty acid synthase in fetal lung. The effect of the hormone appears to be due to increased transcription and post-transcriptional events and is dependent on protein synthesis.

Inhibition of de novo Fatty-Acid Biosynthesis in Isolated Chloroplasts by Different Antibiotics and Herbicides

1989 ◽  
Vol 44 (11-12) ◽  
pp. 976-978 ◽  
Author(s):  
Andrea Feld ◽  
Klaus Kobek ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Fatty Acid Fraction ◽  
Acetate Incorporation ◽  
Acid Biosynthesis ◽  
Dependent Inhibition ◽  
Dicotyledonous Plants ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Abstract Two natural antibiotics, cerulenin and thiolactomycin, were tested for their inhibitory efficacy on de novo fatty-acid biosynthesis of chloroplasts isolated from oat and spinach seedlings and compared with that of known herbicides. With both antibiotics a strong dose-dependent inhibition of the incorporation of [l-14C]acetate into the fatty-acid fraction of the isolated plastids was detected. The l50-values for the inhibition of acetate incorporation into fatty acids are about 4 µM in the case of thiolactomycin and about 50 µM in the case of cerulenin for both mono-and dicotyledonous plants. These values are much higher than those of the particular graminicides cycloxydim and diclofop (0.15 and 0.1 µM), which were developed to control grass weeds in dicotyledonous crop cultures.

Regulation of fatty acid biosynthesis in rats by physical training

1984 ◽  
Vol 56 (4) ◽  
pp. 1060-1064 ◽  
Author(s):  
R. Scorpio ◽  
R. L. Rigsby ◽  
D. R. Thomas ◽  
B. D. Gardner
Keyword(s):  
Fatty Acid ◽  
Physical Training ◽  
Fatty Acid Biosynthesis ◽  
Male Rats ◽  
Maximal Velocity ◽  
Acetyl Coa Carboxylase ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Carboxylase Activity ◽  
Hepatic Fatty Acid

Physical training in the form of long-term nonexhaustive daily exercise was studied as a means of regulating fatty acid biosynthesis. Male rats were required to swim for periods up to 90 min/day. The exercise was carried out 6 days/wk for approximately 11 wk. Hepatic fatty acid biosynthesis and acetyl-CoA carboxylase [acetyl-CoA: CO2 ligase (EC 6.4.1.2)] activities were compared with nonexercised rats. At the end of the training period the exercised rats had a lower rate of fatty acid biosynthesis activity and a lower rate of acetyl-CoA carboxylase activity. The difference in acetyl-CoA carboxylase activity was due to a change in maximal velocity with no significant change in the Michaelis constant for acetyl-CoA. Untrained rats were subjected to a single bout of exercise. They also exhibited lower rates of fatty acid biosynthesis and acetyl-CoA carboxylase activities compared with nonexercised rats. However, the lower rates of these enzyme activities were sustained longer in the physically trained rats compared with the exercised untrained rats after the cessation of exercise. These results implicate acetyl-CoA carboxylase as a control site in the regulation of hepatic fatty acid biosynthesis by both physical training and acute exercise in rats. Possible inhibitory mechanisms are discussed.

Sign in / Sign up

Export Citation Format

Share Document