scholarly journals Mechanism of bile-pigment synthesis in algae. 18O incorporation into phycocyanobilin in the unicellular rhodophyte, Cyanidium caldarium

1980 ◽  
Vol 190 (2) ◽  
pp. 445-449 ◽  
Author(s):  
S B Brown ◽  
A J Holroyd ◽  
R F Troxler
Keyword(s):  
Gas Phase ◽  
Bile Pigment ◽  
Cyanidium Caldarium ◽  
Pigment Synthesis ◽  
Slow Exchange ◽  
Oxygen Atoms

The origin of the lactam oxygen atoms of phycocyanobilin from Cyanidium caldarium was studied using 18O labelling. By inhibiting photosynthesis, a high 18O enrichment was maintained in the gas phase and the resulting incorporation of label showed that the lactam oxygen atoms were derived from two oxygen molecules. Slow exchange of these oxygen atoms with water was demonstrated directly by using H218O.

scholarly journals Bile pigment synthesis in plants. Incorporation of haem into phycocyanobilin and phycobiliproteins in Cyanidium caldarium

1981 ◽  
Vol 194 (1) ◽  
pp. 137-147 ◽  
Author(s):  
S B Brown ◽  
J A Holroyd ◽  
R F Troxler ◽  
G D Offner
Keyword(s):  
Chlorophyll A ◽  
Protoporphyrin Ix ◽  
Bile Pigment ◽  
Cyanidium Caldarium ◽  
Pigment Synthesis ◽  
14C Labelling

A procedure was developed whereby haem was taken up by dark-grown cells of the unicellular rhodophyte Cyanidium caldarium. These cells were subsequently incubated either in the dark with 5-aminolaevulinate, which results in excretion of phycocyanobilin into the suspending medium or incubated in the light, which results in synthesis and accumulation of phycocyanin and chlorophyll a within the cells. Phycocyanobilin was isolated from phycocyanin by cleavage from apoprotein in methanol. Phycocyanobilin prepared from phycocyanin or excreted from cells given 5-aminolaevulinate was methylated and purified by t.l.c. By using 14C labelling either in the haem or in 5-aminolaevulinate administered, haem incorporation into phycocyanobilin was demonstrated in both dark and light systems. Since chlorophyll a synthesized in the light in the presence of labelled haem contained no radioactivity, it was clear that haem was directly incorporated into phycocyanobilin and not first converted into protoporphyrin IX. These results clearly demonstrate phycocyanobilin synthesis via haem and not via magnesium protoporphyrin IX as has also been postulated.

scholarly journals Phycocyanobilin synthesis in the unicellular rhodophyte Cyanidium caldarium

1978 ◽  
Vol 172 (3) ◽  
pp. 569-576 ◽  
Author(s):  
R F Troxler ◽  
P Kelly ◽  
S B Brown
Keyword(s):  
Absorption Spectrum ◽  
Mass Spectrum ◽  
Electronic Absorption ◽  
Bile Pigment ◽  
Cyanidium Caldarium ◽  
Pigment Synthesis ◽  
Structural Identity ◽  
Electron Impact Mass ◽  
Impact Mass

Light is required for synthesis of the accessory photosynethetic pigment phycocyanin in cells of the unicellular rhodophyte Cyanidium caldarium. Phycocyanin is a conjugated protein composed of polypeptide subunits to which the light-absorbing bile pigment chromophore phycocyanobilin is covalently attached. Dark-grown cells of C. caldarium are unable to make phycocyanin, but when incubated in the dark with 5-aminolaevulinate the cells synthesize and excrete a protein-free phycobilin (algal bile pigment) into the suspending medium. The electronic absorption spectrum, electron impact mass spectrum, chromatographic properties and imide products obtained after chronic acid degradation of the excreted phycobilin were identical with those of phycocyanobilin cleaved from phycocyanin in boiling methanol. This establishes the structural identity between the excreted phycobilin, which is the end product of bile-pigment synthesis in vivo, and the chromophore cleaved from phycocyanin in boiling methanol. The significance of the structure of the excreted phycobilin with respect to the events surrounding the assembly of the phycocyanin molecule in vivo is discussed.

Reactivity of amino acid anions with nitrogen and oxygen atoms

2018 ◽  
Vol 20 (7) ◽  
pp. 4990-4996 ◽  
Author(s):  
Zhe-Chen Wang ◽  
Ya-Ke Li ◽  
Sheng-Gui He ◽  
Veronica M. Bierbaum
Keyword(s):  
Amino Acid ◽  
Gas Phase ◽  
Ground State ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Oxygen Atoms

Gas-phase reaction of deprotonated tyrosine with a ground state O atom generates five ionic products.

Oxidation of a Tb2O3(111) Thin Film on Pt(111) by Gas-Phase Oxygen Atoms

2014 ◽  
Vol 118 (36) ◽  
pp. 20916-20926 ◽  
Author(s):  
William Cartas ◽  
Rahul Rai ◽  
Ajinkya Sathe ◽  
Andreas Schaefer ◽  
Jason F. Weaver
Keyword(s):  
Thin Film ◽  
Gas Phase ◽  
Oxygen Atoms

scholarly journals The effect of gabaculine on tetrapyrrole biosynthesis and heterotrophic growth in Cyanidium caldarium

1988 ◽  
Vol 254 (3) ◽  
pp. 907-910 ◽  
Author(s):  
J D Houghton ◽  
L Turner ◽  
S B Brown
Keyword(s):  
Chlorophyll Synthesis ◽  
Similar Rate ◽  
Red Alga ◽  
Heterotrophic Growth ◽  
Tetrapyrrole Biosynthesis ◽  
Cyanidium Caldarium ◽  
Pigment Synthesis ◽  
Subsequent Exposure ◽  
Light Inhibition ◽  
Lag Period

Pigment synthesis in four strains of the unicellular red alga Cyanidium caldarium with different pigment-synthesizing patterns was inhibited in the presence of gabaculine (3-amino-2,3-dihydrobenzoic acid). Parallel inhibition of light-induced chlorophyll and phycocyanin synthesis was observed in strain III-D-2, which only synthesizes pigments in the light. Similar parallel inhibition was observed in the dark in mutant CPD, which is able to synthesize chlorophyll and phycocyanin in the absence of light. Inhibition of pigment synthesis in all strains was overcome by addition of 5-aminolaevulinic acid. Inhibition of phycocyanin synthesis in mutant GGB (unable to synthesize chlorophyll) and inhibition of chlorophyll synthesis in mutant III-C (unable to synthesize phycocyanin) were also observed. Gabaculine also inhibited the heterotrophic growth of C. caldarium in the dark. However, inhibition was overcome after an extended lag period, following which cell growth proceeded at a similar rate to that of control cells not exposed to gabaculine. Heterotrophic growth in cells pre-exposed to gabaculine was not inhibited by subsequent exposure. Possible mechanisms for this adaptation are discussed.

scholarly journals A theoretical study of the gas-phase chemi-ionization reaction between uranium and oxygen atoms

2005 ◽  
Vol 122 (14) ◽  
pp. 144317 ◽  
Author(s):  
Jozef Paulovič ◽  
Laura Gagliardi ◽  
John M. Dyke ◽  
Kimihiko Hirao
Keyword(s):  
Gas Phase ◽  
Theoretical Study ◽  
Ionization Reaction ◽  
Oxygen Atoms
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