41 research outputs found
Flavonoids and a new calamenene-type sesquiterpene from rhizomes of Alpinia oxymitra K. Schum (Zingiberaceae)
Manipulating the Biosynthesis of Bioactive Compound Alkaloids for Next-Generation Metabolic Engineering in Opium Poppy Using CRISPR-Cas 9 Genome Editing Technology
Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated9 (Cas9) endonuclease system is a powerful RNA-guided genome editing tool. CRISPR/Cas9 has been well studied in model plant species for targeted genome editing. However, few studies have been reported on plant species without whole genome sequence information. Currently, no study has been performed to manipulate metabolic pathways using CRISPR/Cas9. In this study, the type II CRISPR/SpCas9 system was used to knock out, via nonhomologous end-joining genome repair, the 4′OMT2 in opium poppy (Papaver somniferum L.), a gene which regulates the biosythesis of benzylisoquinoline alkaloids (BIAs). For sgRNA transcription, viral-based TRV and synthetic binary plasmids were designed and delivered into plant cells with a Cas9 encoding-synthetic vector by Agrobacterium-mediated transformation. InDels formed by CRISPR/Cas9 were detected by sequence analysis. Our results showed that the biosynthesis of BIAs (e.g. morphine, thebaine) was significantly reduced in the transgenic plants suggesting that 4′OMT2 was efficiently knocked-out by our CRISPR-Cas9 genome editing approach. In addition, a novel uncharacterized alkaloid was observed only in CRISPR/Cas9 edited plants. Thus, the applicabilitiy of the CRISPR/Cas9 system was demonstrated for the first time for medicinal aromatic plants by sgRNAs transcribed from both synthetic and viral vectors to regulate BIA metabolism and biosynthesis
A Screening Assay for Neuraminidase Inhibitors Using Neuraminidases N1 and N3 from a Baculovirus Expression System
Callus and suspension culture ofSilybum marianum. Biosynthesis of proteins with clotting activity
The Quenching Effect of Flavonoids on 4-methylumbelliferone, a Potential Pitfall in Fluorimetric Neuraminidase Inhibition Assays
Many assays aimed to test the inhibitory effects of synthetic molecules, and naturally occurring products on the neuraminidase
activity exploit the hydrolysis of 2\u2032-O-(4-methylumbelliferyl)-N-acetylneuraminic acid (4-MUNANA). The amount of
the released product, 4-methylumbelliferone (4-MU), is then measured fluorimetrically. The authors attempted an analysis
of the inhibitory properties of 35 naturally occurring flavonoids on neuraminidase N3, where only 29 of them were sufficiently
soluble in the assay medium. During the analysis, the authors noticed a strong quenching effect due to the test compounds
on the fluorescence of 4-MU. The quenching constants for the flavonoids were determined according to the
Stern-Volmer approach. The extent of fluorescence reduction due to quenching and the magnitude of the fluorescence reduction
measured in the inhibition assays were comparable: for 11 of 29 compounds, the two values were found to be coincident
within the experimental uncertainty. These data were statistically analyzed for correlation by calculating the pertinent
Pearson correlation coefficient. Inhibition and quenching were found to be positively correlated (r = 0.71, p(uncorr) = 1.5
7
10 125), and the correlation was maintained for the whole set of tested compounds. Altogether, the collected data imply that all
of the tested flavonoids could produce false-positive results in the neuraminidase inhibition assay using 4-MUNANA as a
substrate
Terpenoid content and transcription profile analysis in callus and suspension cultures of Croton stellatopilosus
Transcription Profiles Analysis of Genes Encoding 1-Deoxy-D-xylulose 5-Phosphate Synthase and 2C-Methyl-D-erythritol 4-Phosphate Synthase in Plaunotol Biosynthesis from Croton stellatopilosus
Cell-suspension cultures of ononis-natrix L subspecies ramosissima Establishment and culture conditions
Explants from petioles, folioles or hypocotyls of Ononis natrix have been used for calli initiation. Hypocotyls inoculated on MS medium supplemented with 2% sucrose and 0.5 mg.l-1 2,4-D/1 mg.l-1 Kin showed to be the best primary explant. Cell suspension cultures were established in MS basal medium supplemented with 2% sucrose, 0.5 mg.l-1 NAA or 2,4-D and 1 mg.l-1 Kin. Different subculturing periods, inoculum density, hormonal supplementation and sucrose concentration were assayed in order to obtain the best culture growth conditions. The optimal conditions were achieved with cultures initiated with 40 g.l-1 of initial inoculum, growing in MS basal medium supplemented with 4% sucrose, 0.5 mg.l-1 NAA and 1 mg.1-1 Kin subcultured every twelve days. Under these experimental conditions, the cultures showed a doubling time of 36.3 hours