3-Deoxyanthocyanidins are structurally related to the anthocyanin pigments, which are popular as health-promoting phytochemicals. Here, it is demonstrated that the 3-deoxyanthocyanidins are more cytotoxic on human cancer cells than the 3-hydroxylated anthocyanidin analogues. At 200 microM concentration, luteolinidin reduced the viability of HL-60 and HepG2 cells by 90 and 50%, respectively. Sorghum is a major source of 3-deoxyanthocyanidins, which are present as seed pigments and as phytoalexins responding to pathogen attack. On the basis of the collision-induced dissociation spectra of luteolinidin and apigeninidin, an LC-MS/MS method, operating in multiple-reaction monitoring mode, was developed for the specific detection and accurate quantification of these compounds in complex mixtures, which may be difficult to analyze using absorbance measurements. The results demonstrated that inoculated sorghum seedlings could be utilized for convenient and large-scale production of 3-deoxyanthocyanidins. A quantity of almost 270 microg/g (fresh weight) of luteolinidin was produced 72 h after fungal inoculation of 1-week-old seedlings.
Three unique sorghum flavonoid 3'-hydroxylase (F3'H) cDNAs (SbF3'H1, SbF3'H2 and SbF3'H3) were discovered through bioinformatics analysis. Their encoded proteins showed >60% identity to the Arabidopsis TT7 (F3'H) protein. Overexpression of SbF3'H1 or SbF3'H2 restored the ability of tt7 mutants to produce 3'-hydroxylated flavonoids, establishing their roles as functional F3'H enzymes. In sorghum mesocotyls, SbF3'H1 expression was involved in light-specific anthocyanin accumulation while SbF3'H2 expression was involved in pathogen-specific 3-deoxyanthocyanidin synthesis. No SbF3'H3 expression was detected in all tissues examined. The sorghum mesocotyls represent a good system for investigation of differential regulation of F3'H genes/alleles responding to different external stimuli.
Isoflavones are legume-specific flavonoids best known for their potential cancer preventive and phytoestrogenic properties. In this study, we attempted to engineer the isoflavone pathway in the popular fruit crop tomato (Solanum lycopersicum L). Tomato plants were transformed with a soybean (Glycine max L) isoflavone synthase (GmIFS2) cDNA under the control of the cauliflower mosaic virus 35S promoter. LC-MS/MS analysis demonstrated the presence of genistin (genistein 7-O-glucoside) as the major isoflavone metabolite in the transgenic plants. Substantial amounts of genistin (up to 90 nmol/g FW) were found in leaves, while the levels were marginally detectable (less than 0.5 nmol/g FW) in fruit peels. In either case, no drastic variations in endogenous phenolic contents were observed. Fruit peels were found to accumulate high levels of naringenin chalcone, implicating the limitation of naringenin substrates for isoflavone synthesis. Our results suggested that tomato plants could be engineered to produce isoflavones without comprising the levels of endogenous flavonols, which are also health-beneficial, but it may be necessary to enhance the expression levels of chalcone isomerase simultaneously to achieve significant yields in edible tissues such as fruit peels.
Pteroptyx maipo sp. nov. is the first record of the genus Pteroptyx Olivier from mainland China and Hong Kong and represents the most northerly record for this genus. The description includes all life stages: egg, larva, pupa and adult, and covers special structures such as the female bursa plates and male copulatory clamp. Details of habitat, male courtship flash patterns and male-female courtship behaviour are described. This species is the second in the genus Pteroptyx found to use a copulatory clamp, which functions to wedge the mating pair together. A complete clamp however does not appear necessary for successful insemination. Bursa plates hold the spermatophore partially projecting into a spermatophore-digesting gland. Other functions for the plates are investigated and discussed. The deflexed elytral apex appears after eclosion in the adult male. Mechanisms for the loss of ventrite 8 in the male abdomen are explored. A list of the 30 Pteroptyx species recognised here, with habitats, some morphological characteristics and a key to species of the Oriental Pteroptyx are provided.
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