Stran 1 iz 63 rezultatov
A major limitation for the utilization of sorghum forage is the production of the cyanogenic glycoside dhurrin in its leaves and stem that may cause the death of cattle feeding on it at the pre-flowering stage. Therefore, we attempted to develop transgenic sorghum plants with reduced levels of
Flag leaves of 'Colman' forage sorghum (Sorghum bicolor) contain at least 25 times as much leucoanthocyanidin (LAC) and approximately half as much of the cyanogenic glucoside, dhurrin, as do flag leaves of 'White Collier' forage sorghum. Assays of flag leaves from 119 F2 plants and 11 F5 lines from
A novel cyanogenic diglucoside has been isolated from methanolic extracts of young seedlings of Sorghum bicolor. Its structure was established as dhurrin-6-glucoside from NMR, mass spectrometry and enzymatic hydrolysis data. Compared with dhurrin, which is the major cyanogenic glucoside in sorghum
A microsomal fraction from seedlings of Sorghum bicolor (Linn) Moench has been shown to catalyze the conversion of L-tyrosine to p-hydroxymandelonitrile via p-hydroxyphenylacetaldoxime. This transformation is consistent with the general pathway for cyanogenic glycoside biosynthesis proposed on the
The two multifunctional cytochrome P450 enzymes, CYP79A1 and CYP71E1, involved in the biosynthesis of the cyanogenic glucoside dhurrin in Sorghum bicolor (L.) Moench have been characterized with respect to substrate specificity and cofactor requirements using reconstituted, recombinant enzymes and
The heme thiolate protein cytochrome P450tyr is a multifunctional N-hydroxylase converting L-tyrosine to p-hydroxyphenylacetaldehyde oxime in the biosynthesis of the cyanogenic glucoside dhurrin in Sorghum bicolor (Sibbesen et al. (1995) J. Biol. Chem. 270, 3506-3511). Using a polyclonal antibody
The localization of three monooxygenase (hydroxylase) enzyme systems which occur in dark-grown seedlings of Sorghum bicolor has been studied. Cinnamic acid 4-hydroxylase (CAH) (trans-cinnamate 4-monooxygenase, EC 1.14.13.11), which has been increasingly utilized in plants as a marker for the
Spectral scanning was used to provide estimates of the leakage of the cyanogenic glucoside, dhurrin (p-hydroxy-[S]-mandelonitrile-beta-d-glucoside), and its metabolite, p-hydroxybenzaldehyde (p-HB), from young light-grown shoots of Atlas sorghum (Sorghum bicolor [L.] Moench) when these shoots were
Studies with purified mesophyll and epidermal protoplasts and bundle sheath strands have shown that the cyanogenic glucoside dhurrin (p-hydroxy-(S)-mandelonitrile-beta-d-glucoside) is localized in the epidermis of sorghum leaves whereas the enzymes involved in its degradation (dhurrin
Novel cyanogenic plants have been generated by the simultaneous expression of the two multifunctional sorghum (Sorghum bicolor [L.] Moench) cytochrome P450 enzymes CYP79A1 and CYP71E1 in tobacco (Nicotiana tabacum cv Xanthi) and Arabidopsis under the regulation of the constitutive 35S promoter.
Two beta-glucosidases exhibiting high specificity for the cyanogenic glucoside dhurrin have been purified to near homogeneity from seedlings of Sorghum bicolor. Dhurrinase 1 was isolated from shoots of seedlings grown in the dark. Dhurrinase 2 was isolated from the green shoots of young seedlings
The important cereal crop Sorghum bicolor (L.) Moench biosynthesize and accumulate the defensive compound dhurrin during development. Previous work has suggested multiple roles for the compound including a function as nitrogen storage/buffer. Crucial for this function is the endogenous turnover of
Large numbers of vacuoles (10(6)-10(7)) have been isolated from Sorghum bicolor protoplasts and analyzed for the cyanogenic glucoside dhurrin. Leaves from light-grown seedlings were incubated for 4 hours in 1.5% cellulysin and 0.5% macerase to yield mesophyll protoplasts which then were recovered by
Localisation of metabolites in sorghum coleoptiles using Raman hyperspectral imaging analysis was compared in wild type plants and mutants that lack cyanogenic glucosides. This novel method allows high spatial resolution in situ localization by detecting functional groups associated with cyanogenic
Genomic gene clusters for the biosynthesis of chemical defence compounds are increasingly identified in plant genomes. We previously reported the independent evolution of biosynthetic gene clusters for cyanogenic glucoside biosynthesis in three plant lineages. Here we report that the gene cluster