Biosynthesis of Lycomarasmin

Abstract

Cultures of Fusarium oxysporum Schl. emend. Sny. et Hans. f lycopersici (Sacc.) Sny. et Hans. grown on a liquid medium with glucose as the principal carbon source produce, among other products, the phytotoxin lycomarasmin. Acid hydrolysis of lycomarasmin results in the formation of aspartic acid, glycine, and pyruvic acid. Tracer studies showed that glycine-U-I4C, L-serine-U-14C, DL-aspartic acid-4-14C, DL-alanine-1-14C, and glucose-U-14C served as relatively efficient precursors of the lycomarasmin molecule. DL-Aspartic acid-4-I4C was incorporated into the 4-carbon fragment without label scrambling. Glycine was found to be the most efficient precursor of the 2-carbon fragment while glucose afforded the most efficient and direct route for the 3-carbon fragment.

Studies on synthesis of plant growth hormone steroids. Part 16. Stereoselective synthesis of 26,27-dinorbrassinolide

“…The mixture was stirred at room temperature, and the reaction was monitored by TLC [light petroleum-thy1 acetate (3: l)] until the reaction was complete; anhydrous diethyl ether was then added, the mixture was filtered and evaporated, and the residue was purified by flash column chromatography [light petroleum-ethyl acetate (3: l)] to give compound (9) as a solid in quantitative yield, m.p. 215 (10) and (lla and b).-To a solution of compound (9) (30 mg) in ethanol (20 ml) was added Pt02*2H20 (6 mg) and the mixture was hydrogenated at 30 "C and 10°C respectively. The catalyst was filtered off and the solvent was removed to give a mixture of compounds (lla) and (llb) (30 "C) and a mixture of compounds (lo), (lla), and (llb) (10 "C), both in quantitative yield.…”

Identification of the AMA Synthase from the Aspergillomarasmine A Biosynthesis and Evaluation of Its Biocatalytic Potential

“…Melonis , and P. teres. , which were originally shown to cause plants to wilt. − AMA was first isolated from A. oryzae in 1965 . Later, AMA was further found to inhibit angiotensin-converting enzymes through its metal-chelating activity. , As a phytotoxin, AMA was found to participate in the interaction with the host to promote fungi’s growth.…”

“…Although many synthetic studies toward AMA have been reported, the biosynthesis of AMA has yet to be elucidated. Previously, l -serine and d , l -aspartic acid were proven to serve as possible precursors of lycomarasmine through 14 C labeling studies . In 1991, a 14 C labeling experiment also indicated that toxin A ( 3 ) was the biosynthetic precursor of AMA .…”

“…Previously, L-serine and D,L-aspartic acid were proven to serve as possible precursors of lycomarasmine through 14 C labeling studies. 8 In 1991, a 14 C labeling experiment also indicated that toxin A (3) was the biosynthetic precursor of AMA. 11 We are particularly interested in mechanism about how the two C−N bonds of AMA are built in fungi from simple building blocks, i.e.…”