LC-ESI/MS determination of xanthone and secoiridoid glycosides from in vitro regenerated and in vivo Swertia chirayita

A rapid analytical method has been developed to determine xanthone and secoiridoid glycoside in in vitro and in vivo Swertia chirayita extracts. Ultra performance liquid chromatography–electrospray ionization mass spectrometry (LC-ESI/MS) was applied and validated for the analysis of xanthone and secoiridoid glycoside a potential active component isolated from methanolic extracts of in vitro and in vivo Swertia chirayita plantlets. Chromatographic separation was achieved on a RP-C18 column using gradient elution. Mangiferin (Xanthone), Amarogentin and Swertiamarin (Secoiridoid glycosides) were identified in both the extracts. In the LC/ESI-MS spectra, major [M + H] ⁺ and [M + Na] ⁺ ions were observed in positive ion mode and provided molecular mass information. An ultra-performance liquid-chromatography in combination with electrospray ionization tandem mass spectrometry involving metal cationisation was successfully utilized for the rapid identification of xanthone and secoiridoid glycosides. This method is suitable for the routine analysis, as well as for the separation and identification of known and novel secoiridoid glycoside and xanthone.     

Cyclic presence and absence of conspecifics alters circadian clock phase but does not entrain the locomotor activity rhythm of the fruit fly Drosophila melanogaster

Circadian clocks use a wide range of environmental cues, including cycles of light, temperature, food, and social interactions, to fine-tune rhythms in behavior and physiology. Although social cues have been shown to influence circadian clocks of a variety of organisms including the fruit fly Drosophila melanogaster, their mechanism of action is still unclear. Here, the authors report the results of their study aimed at investigating if daily cycles of presence and absence (PA) of conspecific male visitors are able to entrain the circadian locomotor activity rhythm of male hosts living under constant darkness (DD). The results suggest that PA cycles may not be able to entrain circadian locomotor activity rhythms of Drosophila. The outcome does not change when male hosts are presented with female visitors, suggesting that PA cycles of either sex may not be effective in bringing about stable entrainment of circadian clocks in D. melanogaster. However, in hosts whose clock phase has already been set by light/dark (LD) cycles, daily PA cycles of visitors can cause measurable change in the phase of subsequent free-running rhythms, provided that their circadian clocks are labile. Thus, the findings of this study suggest that D. melanogaster males may not be using cyclic social cues as their primary zeitgeber (time cue) for entrainment of circadian clocks, although social cues are capable of altering the phase of their circadian rhythms.     

Development and molecular characterization of wheat--Aegilops kotschyi addition and substitution lines with high grain protein, iron, and zinc

Over two billion people, depending largely on staple foods, suffer from deficiencies in protein and some micronutrients such as iron and zinc. Among various approaches to overcome protein and micronutrient deficiencies, biofortification through a combination of conventional and molecular breeding methods is the most feasible, cheapest, and sustainable approach. An interspecific cross was made between the wheat cultivar 'Chinese Spring' and Aegilops kotschyi Boiss. accession 396, which has a threefold higher grain iron and zinc concentrations and about 33% higher protein concentration than wheat cultivars. Recurrent backcrossing and selection for the micronutrient content was performed at each generation. Thirteen derivatives with high grain iron and zinc concentrations and contents, ash and ash micronutrients, and protein were analyzed for alien introgression. Morphological markers, high molecular weight glutenin subunit profiles, anchored wheat microsatellite markers, and GISH showed that addition and substitution of homoeologous groups 1, 2, and 7 chromosomes of Ae. kotschyi possess gene(s) for high grain micronutrients. The addition of 1U/1S had high molecular weight glutenin subunits with higher molecular weight than those of wheat, and the addition of 2S in most of the derivatives also enhanced grain protein content by over 20%. Low grain protein content in a derivative with a 2S-wheat translocation, waxy leaves, and absence of the gdm148 marker strongly suggests that the gene for higher grain protein content on chromosome 2S is orthologous to the grain protein QTL on the short arm of group 2 chromosomes.     

A novel series of IKKβ inhibitors part II: description of a potent and pharmacologically active series of analogs

A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKβ. In this Letter we document our efforts at further optimization of this series, culminating in 2 with submicromolar potency in a HWB assay and efficacy in a CIA mouse model.     

Brassinin oxidase mediated transformation of the phytoalexin brassinin: structure of the elusive co-product, deuterium isotope effect and stereoselectivity

Brassinin oxidase, a fungal detoxifying enzyme that mediates the conversion of the phytoalexin brassinin into indole-3-carboxaldehyde, is the first enzyme described to date that catalyzes the transformation of a dithiocarbamate group into an aldehyde equivalent. Brassinin is an essential phytoalexin due to its antifungal activity and its role as biosynthetic precursor of other phytoalexins produced in plants of the family Brassicaceae (common name crucifer). In this report, the isolation, structure determination and synthesis of the elusive co-product of brassinin transformation by brassinin oxidase, S-methyl dithiocarbamate, the syntheses of dideuterated and (R) and (S) monodeuterated brassinins, kinetic analyses of isotope effects and chemical modifications of brassinin oxidase are described. The reaction of [1'-(2)H(2)]brassinin was found to be slowed by a kinetic isotope effect of 5.3 on the value of k(cat)/K(m). This result indicates that the hydride/hydrogen transfer step preceding brassinin transformation is rate determining in the overall reaction. In addition, the use of (R) and (S)-[1'-(2)H]brassinins as substrates indicated that the hydride/hydrogen transfer step is ca. 88% stereoselective for the pro-R hydrogen. A detailed chemical mechanism of the enzymatic transformation of brassinin is proposed.