PubMed · 13457453
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
H H GOLZ. 1957. Phosphate ester insecticides.. https://pubmed.ncbi.nlm.nih.gov/13457453/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Representative Boc-protected and acetyl-protected peptide methyl esters bearing alkyl side chains undergo effective oxidation using methyl(trifluoromethyl)dioxirane (1b) under mild conditions. We observe a protecting group dependency in the chemoselectivity displayed by the dioxirane 1b. N-Hydroxylation occurs in the case of the Boc-protected peptides, and side chain hydroxylation takes place in the case of acetyl-protected peptides. Both are attractive transformations since they yield derivatized peptides that serve as valuable synthons.
Fumonisins are carcinogenic mycotoxins produced by the maize ear rot pathogen Gibberella moniliformis (anamorph Fusarium verticillioides). These toxins consist of a linear polyketide-derived backbone substituted at various positions with an amine, one to four hydroxyl, two methyl, and two tricarballylic ester functions. In this study, we generated and characterized deletion mutants of G. moniliformis for five genes, FUM7, FUM10, FUM11, FUM14, and FUM16 in the fumonisin biosynthetic gene cluster. Functional analysis of mutants in four genes, predicted to encode unrelated proteins, affected formation of the tricarballylic esters. FUM7 deletion mutants produced a previously undescribed homologue of fumonisin B1 with an alkene function in both tricarballylic esters, FUM10 and FUM14 deletion mutants produced homologues of fumonisin B3 and fumonisin B4 that lack tricarballylic ester functions, and FUM11 deletion mutants produced fumonisins that lack one of the tricarballylic ester functions. These phenotypes indicated specific roles for FUM7, FUM10, FUM11, and FUM14 in fumonisin biosynthesis that are consistent with the predicted proteins encoded by each gene. Deletion of FUM16 had no apparent effect on fumonisin production. The phenotypes of the deletion mutants provide further insight into the order of steps in fumonisin biosynthesis.
The oxylipin metabolism was analyzed in soybean homogenates containing different sets of lipoxygenase isozymes (L-1, -2, and -3); namely, Suzuyutaka (containing L-1, -2, and -3), Yumeyutaka (containing only L-1), Kanto102 (containing L-2), Kyushu119 (containing L-3), and Ichihime (lacking all three isozymes). The amount of oxidized fatty acids in the esterified form was higher than that in the free form with every cultivar. Kanto102 formed the highest amount of oxidized lipids, and Yumeyutaka and Ichihime formed the lowest. With Kanto102 and Kyushu119, high amounts of keto fatty acids were formed, while they were undetectable with Yumeyutaka and Ichihime. Due to the lack of lipoxygenases in Ichihime, an accumulation of free fatty acids was expected; however, their amount in Yumeyutaka was significantly lower than was expected. It is suggested that a pathway existed to form C6-volatiles through hydroperoxides in the esterified form.