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The article discusses the identification of catalytic amino acid residues of the enzyme lachrymatory factor synthase (LFS) present in onions. It mentions that LFS enzymes synthesizes lachrymatory factor which produces the compound thioaldehyde S-oxides. The two amino acids arginine and glutamic acid were recognized to be essential for LFS activities that were identified through various techniques which include deletion analysis, homology modeling and site-directed mutagenesis.

The article presents a study on the distribution profiles of curcuminoids and dihydrocurcuminoids in cell clumps, roots and leaves of turmeric rhizomes. Metabolites such as dihydrocurcumin and dihydrodesmethoxycurcumin-a were isolated from cultured cell clumps. A comparison between curcuminoids and dihydrocurcuminoids showed that dihydrocurcuminoids was the main colored constituents in cell clumps, roots and leaves while curcumin and dihydrocurcumin were mostly found in leaves and rhizomes.

Through a single genetic transformation in onion (Allium cepa), a crop recalcitrant to genetic transformation, we suppressed the lachrymatory factor synthase gene using RNA interference silencing in six plants. This reduced lachrymatory synthase activity by up to 1,544-fold, so that when wounded the onions produced significantly reduced levels of tear-inducing lachrymatory factor. We then confirmed, through a novel colorimetric assay, that this silencing had shifted the trans-S-1-propenyl-L-cysteine sulfoxide breakdown pathway so that more 1-propenyl sulfenic acid was converted into di-1-propenyl thiosulfinate. A consequence of this raised thiosulfinate level was a marked increase in the downstream production of a nonenzymatically produced zwiebelane isomer and other volatile sulfur compounds, di-1-propenyl disulfide and 2-mercapto-3,4-dimethyl-2,3- dthydrothiophene, which had previously been reported in trace amounts or had not been detected in onion. The consequences of this dramatic simultaneous down- and up-regulation of secondary sulfur products on the health and flavor attributes of the onion are discussed. [ABSTRACT FROM AUTHOR]

The article presents a study regarding the biosynthesis of curcuminoid in rhizomes of turmeric (Curcuma longa). It explains that curcuminoids are yellow pigments that accumulate rhizomes of turmeric. The analyses shows that incorporation of efficiencies of the same precursors into desmethoxycurcumin (DMC) and curcumin were similar. Thus, it reveals the possibility that pathway to curcuminoids utilized two cinnamoyl CoAs and one malonyl CoA.

Describes a polymerase chain reaction method for the detection of buckwheat DNA using primers corresponding to internal transcribed spacer region. Information on the presence of buckwheat contamination in food; Causes of allergies; Risk of raising the buckwheat allergy due to allergens derived from wild buckwheat.

The article offers information on a study related to proton transfer in a reaction catalyzed by onion lachrymatory factor synthase. It informs about production of single deuterated lachrymatory factor in a model reaction system comprising purified alliinase, lachrymatory factor synthase (LFS), cysteine sulfoxide.