A study on the biosynthesis of hygrophorone B12 in the mushroom Hygrophorus abieticola reveals an unexpected labelling pattern in the cyclopentenone moiety

2015 ◽  
Vol 118 ◽  
pp. 174-180 ◽  
Author(s):  
Alexander Otto ◽  
Andrea Porzel ◽  
Jürgen Schmidt ◽  
Ludger Wessjohann ◽  
Norbert Arnold
Keyword(s):  
Labelling Pattern

SYNTHESIS OF RAFFINOSE IN SPRUCE TWIGS

1963 ◽  
Vol 41 (12) ◽  
pp. 1681-1686 ◽  
Author(s):  
Dora Rast ◽  
A. G. McInnes ◽  
A. C. Neish
Keyword(s):  
Seasonal Variation ◽  
Labelling Pattern

Detached spruce twigs were allowed to photosynthesize in C14O2, or were fed labelled glucose, fructose, or galactose through the stem. The sucrose and raffinose formed were isolated and the distribution of C14 between their constituent monosaccharides was determined. Raffinose formed photosynthetically had a relatively low amount of C14 in its galactose moiety. The actual labelling pattern showed a seasonal variation but raffinose seems to be synthesized by galactosylation of uniformly labelled sucrose. When monosaccharides were administered through the stem it appears that two different pools of sucrose are involved, one of which is not uniformly labelled. This is discussed in relation to transport of sugars.

scholarly journals The mechanism of haem catabolism. Bilirubin formation in living rats by [18O]oxygen labelling

1978 ◽  
Vol 170 (2) ◽  
pp. 297-311 ◽  
Author(s):  
S B Brown ◽  
R F G J King
Keyword(s):  
Mass Spectrum ◽  
Bile Duct ◽  
Common Bile Duct ◽  
Labelling Pattern ◽  
Chemical Transformations ◽  
Not Given ◽  
Significant Extent ◽  
Catabolic Pathway ◽  
The Common ◽  
Quantitative Recovery

1. The pathway of haem breakdown in living rats was studied by using 18O in the oxygen that the animals consumed. By cannulation of the common bile duct and collection of bile, labelled bilirubin was isolated and its mass spectrum determined. One set of results was obtained for a rat to which haemoglobin had been intravenously administered and another set obtained for a rat that was not given exogenous haem. Isomerization of bilirubin IXalpha to the XIIIalpha and IIIalpha isomers did not occur to any significant extent. The 18O-labelling pattern obtained in the bilirubin was consistent with a Two-Molecule Mechanism, whereby the terminal lactam oxygen atoms of bilirubin are derived from different oxygen molecules. The consequences of this mechanism are discussed in terms of the possible intermediates of the catabolic pathway. 2. 18O-labelled bilirubin appeared in the bile in less than 10 min after exposure of the animals to labelled oxygen. This result suggests that all of the chemical transformations involving production of biliverdin, reduction to bilirubin and conjugation of the bilirubin are fast processes. 3. The quantitative recovery of label obtained in the experiments suggests that there is little or no exchange of newly synthesized bilirubin with existing bilirubin pools in the animal.

scholarly journals Biosynthesis of geraniol and nerol and their β-d-glucosides in Perlargonium graveolens and Rosa dilecta

1972 ◽  
Vol 130 (4) ◽  
pp. 1045-1054 ◽  
Author(s):  
Derek V. Banthorpe ◽  
Geoffrey N. J. Le Patourel ◽  
Martin J. O. Francis
Keyword(s):  
Double Bond ◽  
Hydrogen Atom ◽  
Higher Plants ◽  
Animal Tissue ◽  
Labelling Pattern ◽  
Isopentenyl Pyrophosphate ◽  
Pelargonium Graveolens ◽  
Dimethylallyl Pyrophosphate

1. 3R-[2-14C]Mevalonate was incorporated into geranyl and neryl β-d-glucosides in petals of Rosa dilecta in up to 10.6% yield, and the terpenoid part was specifically and equivalently labelled in the moieties derived from isopentenyl pyrophosphate and 3,3-dimethylallyl pyrophosphate. A similar labelling pattern, with incorporations of 0.06–0.1% was found for geraniol or nerol formed in leaves of Pelargonium graveolens The former results provide the best available evidence for the mevalonoid route to regular monoterpenes in higher plants. 2. Incorporation studies with 3RS-[2-14C,(4R)-4-3H1]-mevalonate and its (4S)-isomer showed that the pro-4R hydrogen atom of the precursor was retained and the pro-4S hydrogen atom was eliminated in both alcohols and both glucosides. These results suggest that the correlation of retention of the pro-4S hydrogen atom of mevalonate with formation of a cis-substituted double bond, such as has been found in certain higher terpenoids, does not apply to the biosynthesis of monoterpenes. It is proposed that either nerol is derived from isomerization of geraniol or the two alcohols are directly formed by different prenyltransferases. Possible mechanisms for these processes are discussed. 3. The experiments with [14C,3H]mevalonate also show that in these higher plants, as has been previously found in animal tissue and yeast, the pro-4S hydrogen atom of mevalonate was lost in the conversion of isopentenyl pyrophosphate into 3,3-dimethylallyl pyrophosphate.

The biosynthesis of the new tremulane sesquiterpenes isolated from Phellinustremulae

1997 ◽  
Vol 75 (6) ◽  
pp. 834-839 ◽  
Author(s):  
Elizabete R. Cruz
Keyword(s):  
Spectral Analysis ◽  
Sodium Acetate ◽  
Labelling Pattern ◽  
Farnesyl Pyrophosphate ◽  
Fungal Metabolites ◽  
Methyl Group ◽  
Liquid Cultures ◽  
C Nmr

The tremulane sesquiterpenes isolated from the wood-rotting fungus Phellinustremulae are irregular isoprenoids derived from the cyclization and rearrangement of farnesyl pyrophosphate (FPP). The most interesting feature in the formation of the tremulane skeleton seems to involve the migration of a methyl group from one of the isoprene units. To investigate the biosynthetic origin of this unique sesquiterpene skeleton, labelling experiments were carried out by adding 13C-labelled sodium acetate to liquid cultures of Phellinustremulae. The labelling pattern was determined by 13C NMR spectral analysis of labelled tremulenediol A, which was purified as its di-p-bromobenzoate. A possible route to the tremulane skeleton, which accounts for the observed labelling pattern, proceeds from FPP, via humulene. The stereochemical course of the tremulane biosynthesis is discussed. Keywords: fungal metabolites, aspen, perhydroazulene sesquiterpenes, labelling experiments.

Accumulation and Biosynthesis of Solanapyrone Phytotoxins by Ascochyta rabiei

1995 ◽  
Vol 50 (3-4) ◽  
pp. 181-185
Author(s):  
Gregor Benning ◽  
Wolfgang Barz
Keyword(s):  
Stationary Phase ◽  
Secondary Metabolism ◽  
Carbon Skeleton ◽  
Labelling Pattern ◽  
Ascochyta Rabiei ◽  
Phytopathogenic Fungus ◽  
Typical Pattern ◽  
Accumulation Kinetics ◽  
Tracer Experiments

The biosynthesis of the phytotoxins solanapyrone A , B and C produced by the phytopathogenic fungus Ascochyta rabiei has been investigated. To optimize feeding conditons for the tracer experiments the growth of the fungus and the accumulation of the toxins in submers culture were determined. The accumulation kinetics revealed that formation of the toxins occurs in the stationary phase of the growth indicating that synthesis of solanapyrones follows a typical pattern of secondary metabolism. Incorporation experiments with sodium [1-14C]- and [2-13C]acetate were performed and the NMR-spectroscopically determined labelling pattern of the 13C-enriched solanapyrone A compound confirmed that the carbon skeleton of this compound is formed via the polyketide pathway. The biosynthetic route to solanapyrone B is discussed.

Mycoplasma contamination of cell cultures *1Interference with 32P-labelling pattern of RNA

1969 ◽  
Vol 57 (2-3) ◽  
pp. 374-384 ◽  
Author(s):  
G MARKOV ◽  
I BRADVAROVA ◽  
A MINTCHEVA ◽  
P PETROV ◽  
N SHISHKOV ◽  
...  
Keyword(s):  
Cell Cultures ◽  
Labelling Pattern ◽  
Mycoplasma Contamination

scholarly journals Labelling by axonal transport of myelin-associated proteins in the rabbit visual pathway

1981 ◽  
Vol 196 (2) ◽  
pp. 537-545 ◽  
Author(s):  
P P Giorgi ◽  
H DuBois
Keyword(s):  
Axonal Transport ◽  
Sodium Dodecyl ◽  
Specific Radioactivity ◽  
Visual Pathway ◽  
Water Soluble ◽  
Labelling Pattern ◽  
Myelin Proteins ◽  
Survival Times ◽  
Anterograde Axonal Transport ◽  
Associated Proteins

After intraocular injections of [3H]leucine, six regions of the visual pathway of adult rabbit were used to study the spatio-temporal pattern of the slow anterograde axonal transport of radioactive proteins associated with the particulate fraction, the water-soluble fraction and the myelin fraction. Unlike other fractions, myelin-associated labelled proteins represented a time-constant (for a given region) percentage of total tissue radioactivity. This percentage increased from the first half to the second half of the optic nerve and remained high in the chiasma and tract. The peak specific radioactivity of myelin decreased in the same direction. Myelin proteins were separated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and the labelling patterns obtained in different regions and at different survival times were compared. At the peak of myelin radioactivity of a given region the label was typically associated with four protein bands, L1, L2, L3 and L4, of 40000, 44000, 62000, and 68000 mol.wts. respectively. The basic protein, the proteolipid protein and the W1 component (mol.wt. 51000-53000) of the Wolfgram proteins were not significantly labelled. The radioactivity associated with the W2 component (mol.wt 60000) of the Wolfgram proteins could be derived from the closely migrating L3 component. At shorter survival times no clear labelling pattern could be detected. At longer survival times radioactivity was almost totally localized around band L3. The results presented underline the importance of choosing appropriate experimental conditions to obtain a consistent labelling pattern of myelin-associated proteins and to investigate the possible mechanism responsible for this phenomenon.

Sign in / Sign up

Export Citation Format

Share Document