scholarly journals Incorporation of [14C]shikimate into phenazines and their further metabolism by Pseudomonas phenazinium

1977 ◽  
Vol 164 (1) ◽  
pp. 139-145 ◽  
Author(s):  
Graham S. Byng ◽  
John M. Turner
Keyword(s):  
Culture Media ◽  
Kinetic Studies ◽  
Exponential Phase ◽  
Late Exponential Phase ◽  
Pigment Formation ◽  
Naturally Occurring ◽  
Common Precursor ◽  
The Common

1. During growth of Pseudomonas phenazinium on l-threonine medium, phenazine pigment formation commenced early and 1,6-dihydroxyphenazine 5,10-dioxide (iodinin) was the major component. Growth on l-[U-14C]threonine showed that when growth was complete about 25% of the label had been incorporated into phenazines and 30% into cell substance. 2. The addition of d-[2,3,4,5(n)-14C]shikimate to cultures at different phases of growth showed that the greatest efficiency of incorporation (about 70%) occurred in the mid- to late-exponential phase. Phenazines accounting for most of the 14C supplied were iodinin and 9-hydroxyphenazine-1-carboxylate plus 2,9-dihydroxyphenazine-1-carboxylate. Radioactivity incorporated into cell substance was about one-third of the amount found in phenazines. 3. Kinetic studies showed that radioactivity from a pulse of [14C]-shikimate was incorporated into phenazines immediately, without a discernible lag, and into all detectable phenazines simultaneously rather than sequentially. 4. Radioactive phenazines isolated from culture media were fed to growing cultures and their metabolism was studied. The results supported a scheme for the biosynthesis of iodinin and 1,8-dihydroxyphenazine 10-monoxide by a branched pathway. 5. It is proposed that phenazine-1,6-dicarboxylate is the common precursor of all naturally occurring phenazines.

scholarly journals Defining the subcellular distribution and metabolic channeling of phosphatidylinositol

2020 ◽  
Vol 219 (3) ◽  
Author(s):  
Joshua G. Pemberton ◽  
Yeun Ju Kim ◽  
Jana Humpolickova ◽  
Andrea Eisenreichova ◽  
Nivedita Sengupta ◽  
...  
Keyword(s):  
Golgi Complex ◽  
Kinetic Studies ◽  
Intact Cells ◽  
Metabolic Channeling ◽  
Bacterial Enzyme ◽  
Common Precursor ◽  
Steady State Levels ◽  
The Common ◽  
A Minor ◽  
The Relationship

Phosphatidylinositol (PI) is an essential structural component of eukaryotic membranes that also serves as the common precursor for polyphosphoinositide (PPIn) lipids. Despite the recognized importance of PPIn species for signal transduction and membrane homeostasis, there is still a limited understanding of the relationship between PI availability and the turnover of subcellular PPIn pools. To address these shortcomings, we established a molecular toolbox for investigations of PI distribution within intact cells by exploiting the properties of a bacterial enzyme, PI-specific PLC (PI-PLC). Using these tools, we find a minor presence of PI in membranes of the ER, as well as a general enrichment within the cytosolic leaflets of the Golgi complex, peroxisomes, and outer mitochondrial membrane, but only detect very low steady-state levels of PI within the plasma membrane (PM) and endosomes. Kinetic studies also demonstrate the requirement for sustained PI supply from the ER for the maintenance of monophosphorylated PPIn species within the PM, Golgi complex, and endosomal compartments.

scholarly journals Characterization of a Natural, Stable, Reversible and Colourful Anthocyanidin Network from Sphagnum Moss Based Mainly on the Yellow Trans-Chalcone and Red Flavylium Cation Forms

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 709
Author(s):  
Helge Berland ◽  
Øyvind M. Andersen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Cell Wall ◽  
Peat Moss ◽  
Sphagnum Moss ◽  
Naturally Occurring ◽  
Two Component ◽  
Colour System ◽  
The Common ◽  
Cis And Trans

Anthocyanins with various functions in nature are one of the most important sources of colours in plants. They are based on anthocyanidins or 3-deoxyanthocyanidins having in common a C15-skeleton and are unique in terms of how each anthocyanidin is involved in a network of equilibria between different forms exhibiting their own properties including colour. Sphagnorubin C (1) isolated from the cell wall of peat moss (Sphagnum sp.) was in fairly acidic and neutral dimethyl sulfoxide characterized by nuclear magnetic resonance (NMR) and ultraviolet–visible (UV–vis) absorption techniques. At equilibrium, the network of 1 behaved as a two–component colour system involving the reddish flavylium cationic and the yellow trans–chalcone forms. The additional D- and E-rings connected to the common C15-skeleton extend the π-conjugation within the molecule and provide both bathochromic shifts in the absorption spectra of the various forms as well as a low isomerization barrier between the cis- and trans-chalcone forms. The hemiketal and cis-chalcone forms were thus not observed experimentally by NMR due to their short lives. The stable, reversible network of 1 with good colour contrast between its two components has previously not been reported for other natural anthocyanins and might thus have potential in future photochromic systems. This is the first full structural characterization of any naturally occurring anthocyanin chalcone form.

scholarly journals cDNA sequence of human β-preprotachykinin, the common precursor to substance P and neurokinin A

FEBS Letters ◽  
1986 ◽  
Vol 208 (1) ◽  
pp. 67-72 ◽  
Author(s):  
A.J. Harmar ◽  
A. Armstrong ◽  
J.C. Pascall ◽  
K. Chapman ◽  
R. Rosie ◽  
...  
Keyword(s):  
Substance P ◽  
Cdna Sequence ◽  
Neurokinin A ◽  
Common Precursor ◽  
The Common

Brown pigmentation of Xanthomonas campestris pv. phaseoli associated with homogentisic acid

1994 ◽  
Vol 40 (1) ◽  
pp. 28-34 ◽  
Author(s):  
P. H. Goodwin ◽  
C. R. Sopher
Keyword(s):  
Xanthomonas Campestris ◽  
Culture Media ◽  
Taxonomic Status ◽  
Homogentisic Acid ◽  
Brown Pigment ◽  
Pigment Formation ◽  
Dihydroxyphenylacetic Acid ◽  
Alkaline Conditions ◽  
The Media ◽  
Number Of Bacteria

The diffusible brown pigment produced by some strains of Xanthomonas campestris pv. phaseoli was found to be due to the secretion and subsequent oxidation of homogentisic acid (2, 5-dihydroxyphenylacetic acid) rather than tyrosinase activity as previously reported. Homogentisic acid is an intermediate in tyrosine catabolism for a number of bacteria. Brown-pigmented strains appeared to be disrupted in tyrosine catabolism and could not use tyrosine as a nutrient. Nonpigmented strains, however, could utilize tyrosine as a nutrient, and although they secreted homogentisic acid, the levels were approximately 1/100th that of brown-pigmented strains. Production of brown pigment was stimulated by tyrosine and repressed by glucose. Growth in glucose resulted in a drop in the pH of the media, and the greatest pigment formation was associated with a shift to alkaline conditions in the culture media. By buffering the media near pH 7.0, brown pigment formation was repressed, even though unoxidized homogentisic acid accumulated in the culture media. The disruption of tyrosine catabolism corresponds to other reports describing differences between brown-pigmented and nonpigmented strains, and provides further support for the retention of a special taxonomic status for the brown-pigmented strains.Key words: homogentisic acid, pigments, Xanthomonas, fuscans.

Reply to D. C. Mirhady: Torture and rhetoric in Athens

1996 ◽  
Vol 116 ◽  
pp. 132-134 ◽  
Author(s):  
Gerhard Thür
Keyword(s):  
Recent Article ◽  
Procedural Law ◽  
Strong Point ◽  
Common Precursor ◽  
Oral Testimony ◽  
Specialist Knowledge ◽  
The Common

The strong point of D. Mirhady's work (hereafter ‘M.’) lies in his interpretation of the rhetorical handbooks (technai). I agree in general with Part III, though admitting my lack of specialist knowledge in this field. To a large extent Part III confirms my observations on procedural law published in 1977 (Beweisführung, quoted supra n. 4). I approve of the opinion that, despite the use of written rather than oral testimony, the formulas, by which the evidence was used, did not change (M. after n. 62, see my recent article in: Die athenische Demokratie, ed. W. Eder [Stuttgart 1995], p. 329 f.). M. states an appealing hypothesis, that the introduction of written testimony did not so much change the procedure as provide the cause for a new handbook on rhetoric to be written, which he suggests was the common precursor to Aristotle and Anaximenes.

Enhancement of pheomelanogenesis by L-dopa in the mouse melanocyte cell line, TM10, in vitro

1987 ◽  
Vol 87 (4) ◽  
pp. 507-512
Author(s):  
C. Sato ◽  
S. Ito ◽  
T. Takeuchi
Keyword(s):  
Cell Line ◽  
Growth Medium ◽  
Yellow Pigment ◽  
Black Pigment ◽  
Established Cell Line ◽  
Treatment Results ◽  
Common Precursor ◽  
Established Cell ◽  
The Common

Cells of TM10, an established cell line, are melanocytes that contain equal amounts of eumelanin (black pigment) and pheomelanin (yellow pigment). The content of pheomelanin drastically increased when the cells were cultured in growth medium containing 0.2mM-L-dopa (L-dihydroxyphenylalanine), which is the common precursor for both eumelanogenesis and pheomelanogenesis. After this treatment, the amount of pheomelanin was 3.7-fold greater than that of control in TM10, whereas the amount of eumelanin changed very little. In contrast, 5-S-cysteinyl-dopa, which is the specific precursor for pheomelanogenesis downstream of L-dopa, did not cause preferential increase in pheomelanogenesis. Ultrastructural observations also confirmed these results; in 0.2mM-L-dopa, an increase in the number of pheomelanosomes was observed in the cytoplasm of TM10 cells. Our results also suggest that the L-dopa treatment results in a decrease in tyrosinase activity per melanosome.

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