ZfN: Search Results

1	Author	Andrea Feld, Klaus Kobek, HartmutK. Lichtenthaler	Requires cookie*
	Title	Inhibition of de novo Fatty-Acid Biosynthesis in Isolated Chloroplasts by Different Antibiotics and Herbicides
	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 /50-values for the inhibition of acetate incorporation into fatty acids are about 4 fiM in the case of thiolactomycin and about 50 ^im 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 ^im), which were developed to control grass weeds in dicotyledonous crop cultures.
	Reference	Z. Naturforsch. 44c, 976 (1989); received July 3 1989
	Published	1989
	Keywords	Cerulenin, de novo Fatty-Acid Biosynthesis, Isolated Chloroplasts, Thiolactomycin
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	TEI-XML for	default:Reihe_C/44/ZNC-1989-44c-0976.pdf
	Identifier	ZNC-1989-44c-0976
	Volume	44

2	Author	Bernd Listab, A.Ndrea Golza, Wilhelm Bolandb, H. Artm, K. Lichtenthaler3	Requires cookie*
	Title	Inhibition of de novo Fatty-Acid Biosynthesis in Isolated Chloroplasts by the Antibiotic Cerulenin and Its Synthetic Derivatives
	Abstract	The antibiotic cerulenin was shown to be a potent dose-dependent inhibitor o f de novo fatty-acid biosynthesis in intact isolated chloroplasts o f different plants (measured as [l4C]acetate incorporation into the total fatty-acid fraction). Various chemical derivatives o f cerulenin were synthesized and tested in the chloroplast assay-system o f oat, spinach and pea. M odifica tions o f the hydrocarbon chain o f cerulenin (e.g. tetrahydro-cerulenin and its short-chain c«-2,3-epoxy-4-oxoheptanam ide derivative) decreased the inhibitory activity o f cerulenin, whereas variations o f the epoxy-oxo-am ide structural element led to a com plete loss o f inhibi tion potency. The results indicate that the naturally occurring antibiotic cerulenin is the most active specific inhibitor o f de novo fatty-acid biosynthesis, but the form ation o f the hydroxy-lactam ring seems to be an essential requirement for the inhibitory activity. Those structural analogues o f cerulenin, which can no longer form a hydroxylactam ring, do not possess any inhibitory capacity.
	Reference	Z. Naturforsch. 47c, 382 (1992); received March 10 1992
	Published	1992
	Keywords	Cerulenin, Cerulenin Derivatives, de novo Fatty Acid Biosynthesis, Isolated Chloroplasts
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	TEI-XML for	default:Reihe_C/47/ZNC-1992-47c-0382.pdf
	Identifier	ZNC-1992-47c-0382
	Volume	47

3	Author	Klaus Kobek, Manfred Focke, HartmutK. Lichtenthaler	Requires cookie*
	Title	Fatty-Acid Biosynthesis and Acetyl-CoA Carboxylase as a Target of Diclofop, Fenoxaprop and other Aryloxy-phenoxy-propionic Acid Herbicides
	Abstract	The effect of the herbicides and aryloxy-phenoxy-propionic acid derivatives diclofop, fenoxa-prop, 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 sensi-tive grasses (Poaceae) and tolerant dicotyledonous plants (Pisum, Spinacia). The 4 herbicides (free-acid form) block the de novo fatty-acid biosynthesis ([2-l4 C]acetate incorporation into the total fatty-acid fraction) of the sensitive Avena chloroplasts in a dose-dependent manner. The / 50 -values (a 50% inhibition of the [ 14 C]acetate incorporation) lie in the range of 10~ 7 to 2 x 10~ 6 M. 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 concentra-tion of ca. 10" 4 M. 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 [ 14 C]acetate and [ 14 C]acetyl-CoA is blocked by all 4 herbi-cides (free acids), whereas that of [ l4 C]malonate and [ I4 C]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 carboxyl-ase. 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.
	Reference	Z. Naturforsch. 43c, 47—54 (1988); received November 2 1987
	Published	1988
	Keywords	Acetyl-CoA Carboxylase, Chloroplast Metabolism, de novo Fatty-Acid Biosynthesis, Fluazifop, Haloxyfop, Herbicide Sensitivity
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	TEI-XML for	default:Reihe_C/43/ZNC-1988-43c-0047.pdf
	Identifier	ZNC-1988-43c-0047
	Volume	43