scholarly journals The biosynthesis of the chromophore of phycocyanin. Pathway of reduction of biliverdin to phycocyanobilin

1989 ◽  
Vol 261 (1) ◽  
pp. 259-263 ◽  
Author(s):  
S B Brown ◽  
J A Holroyd ◽  
D I Vernon ◽  
Y K Shim ◽  
K M Smith
Keyword(s):  
Photosynthetic Pigments ◽  
Direct Proof ◽  
Cyanidium Caldarium ◽  
The Third ◽  
Biliverdin Ix

The later stages in the pathway of biosynthesis of phycocyanobilin, the chromophore of phycocyanin, were studied by using radiolabelled intermediates. Three possible pathways from biliverdin IX-alpha to phycocyanobilin were considered. 14C-labelled samples of key intermediates in two of the pathways, 3-vinyl-18-ethyl biliverdin IX-alpha and 3-ethyl-18-vinyl biliverdin IX-alpha, were synthesized chemically and were administered to cultures of Cyanidium caldarium that were actively synthesizing photosynthetic pigments in the light. Neither of these two compounds was apparently incorporated into the phycobiliprotein chromophore, suggesting that two of the three pathways were not operative. By elimination, the results imply that the third possible pathway, which involves phytochromobilin, the chromophore of phytochrome, represents the route for biosynthesis of phycocyanobilin. Unfortunately, since 14C-labelled phytochromobilin is not available, no direct proof of this pathway could be obtained. However, if correct, the present interpretation represents a unified pathway for biosynthesis of all plant bilins, via the intermediacy of phytochromobilin.

scholarly journals Biosynthesis of phycobiliproteins. Incorporation of biliverdin into phycocyanin of the red alga Cyanidium caldarium

1984 ◽  
Vol 219 (3) ◽  
pp. 905-909 ◽  
Author(s):  
S B Brown ◽  
J A Holroyd ◽  
D I Vernon
Keyword(s):  
Photosynthetic Pigments ◽  
Red Alga ◽  
Cyanidium Caldarium ◽  
Biliverdin Ix

14C-labelled biliverdin IX alpha was administered to cultures of Cyanidium caldarium that were actively synthesizing photosynthetic pigments in the light. Between 9 and 12% of the phycobiliprotein chromophore produced in such cultures was derived from exogenous biliverdin. These results demonstrate that biliverdin is an intermediate in the biosynthesis of phycobiliproteins.

Biliverdin IX α, Intermediate and End Product of Tetrapyrolle Biosynthesis

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1057-1063 ◽  
Author(s):  
Hans-Peter Köst ◽  
Eva Benedikt
Keyword(s):  
Aminolevulinic Acid ◽  
Chromic Acid ◽  
Protoporphyrin Ix ◽  
Chloroform Extract ◽  
Cyanidium Caldarium ◽  
Green Pigment ◽  
Acid Degradation ◽  
Turdus Merula ◽  
Egg Shells ◽  
Biliverdin Ix

Abstract Dark-grown cells of the unicellular rhodophyte Cyanidium caldarium were incubated with 17 mmol/l 5-aminolevulinic acid in the dark. The excreted pigments were extracted with chloroform and butanol. The presence of biliverdin IX α in the chloroform-extract (besides phycocyanobilin and other pigments) was demonstrated using TLC, HPLC and chromic acid degradation. A pathway leading to phycocyanobilin is discussed. A green pigment from egg shells of Turdus merula (black bird) was also identified as biliverdin IX α with small amounts of protoporphyrin IX, using the same methods as above.

scholarly journals Ferrochelatase activity in the photosynthetic alga Cyanidium caldarium. Development of the enzyme during biosynthesis of photosynthetic pigments

1984 ◽  
Vol 220 (3) ◽  
pp. 861-863 ◽  
Author(s):  
S B Brown ◽  
J A Holroyd ◽  
D I Vernon ◽  
O T G Jones
Keyword(s):  
Photosynthetic Pigments ◽  
Enzyme Preparation ◽  
Crude Enzyme ◽  
Cyanidium Caldarium ◽  
Crude Enzyme Preparation

Dark-grown cells of the photosynthetic alga Cyanidium caldarium were shown to contain ferrochelatase activity, which increased markedly when the cells were induced to form pigments by exposure to light. Km values for the crude enzyme preparation were 14.8 microM and 6.5 microM for binding of Co2+ and deuteroporphyrin IX respectively.

scholarly journals The effect of N-methylprotoporphyrin IX on the synthesis of photosynthetic pigments in Cyanidium caldarium. Further evidence for the role of haem in the biosynthesis of plant bilins

1982 ◽  
Vol 208 (2) ◽  
pp. 487-491 ◽  
Author(s):  
Stanley B. Brown ◽  
J. Andrew Holroyd ◽  
David I. Vernon ◽  
Robert F. Troxler ◽  
Kevin M. Smith
Keyword(s):  
Chlorophyll A ◽  
Photosynthetic Pigments ◽  
Control Mechanism ◽  
Cyanidium Caldarium

N-Methylprotoporphyrin IX strongly inhibits synthesis of phycocyanobilin, but not chlorophyll a, in the dark. In the light, both phycocyanin and chlorophyll a synthesis are inhibited in parallel. These results are consistent with the intermediacy of haem in algal bilin synthesis and suggest a control mechanism for chlorophyll a synthesis, previously unknown.

Progress report on 21-cm observations at low latitude between longitudes (l 11) 0° and 66°

1967 ◽  
Vol 31 ◽  
pp. 177-179
Author(s):  
W. W. Shane
Keyword(s):  
Preliminary Report ◽  
Progress Report ◽  
Galactic Centre ◽  
Low Latitude ◽  
The Third ◽  
Introductory Lecture ◽  
Centre Region

In the course of several 21-cm observing programmes being carried out by the Leiden Observatory with the 25-meter telescope at Dwingeloo, a fairly complete, though inhomogeneous, survey of the regionl11= 0° to 66° at low galactic latitudes is becoming available. The essential data on this survey are presented in Table 1. Oort (1967) has given a preliminary report on the first and third investigations. The third is discussed briefly by Kerr in his introductory lecture on the galactic centre region (Paper 42). Burton (1966) has published provisional results of the fifth investigation, and I have discussed the sixth in Paper 19. All of the observations listed in the table have been completed, but we plan to extend investigation 3 to a much finer grid of positions.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Monte Carlo Algorithms for Moments of Transition Arrays

1988 ◽  
Vol 102 ◽  
pp. 79-81
Author(s):  
A. Goldberg ◽  
S.D. Bloom
Keyword(s):  
Monte Carlo ◽  
State Vector ◽  
Basis Vector ◽  
Collective State ◽  
Dispersion Characteristics ◽  
Dipole Strength ◽  
The Third ◽  
Monte Carlo Algorithms ◽  
Third Moment ◽  
Very High

AbstractClosed expressions for the first, second, and (in some cases) the third moment of atomic transition arrays now exist. Recently a method has been developed for getting to very high moments (up to the 12th and beyond) in cases where a “collective” state-vector (i.e. a state-vector containing the entire electric dipole strength) can be created from each eigenstate in the parent configuration. Both of these approaches give exact results. Herein we describe astatistical(or Monte Carlo) approach which requires onlyonerepresentative state-vector |RV> for the entire parent manifold to get estimates of transition moments of high order. The representation is achieved through the random amplitudes associated with each basis vector making up |RV>. This also gives rise to the dispersion characterizing the method, which has been applied to a system (in the M shell) with≈250,000 lines where we have calculated up to the 5th moment. It turns out that the dispersion in the moments decreases with the size of the manifold, making its application to very big systems statistically advantageous. A discussion of the method and these dispersion characteristics will be presented.

Ultrastructural Localization of Phycocyanin in the Acidophilic, Thermophilic Alga, Cyanidium Caldarium

1973 ◽  
Vol 31 ◽  
pp. 462-463
Author(s):  
M. R. Edwards ◽  
J. D. Mainwaring
Keyword(s):  
Yellowstone National Park ◽  
National Park ◽  
Ultrastructural Localization ◽  
Review Of Literature ◽  
Cyanidium Caldarium ◽  
Taxonomic Rank ◽  
Thin Sections ◽  
Standard Methods ◽  
Laboratory Cultures

Although the general ultrastructure of Cyanidium caldarium, an acidophilic, thermophilic alga of questionable taxonomic rank, has been extensively studied (see review of literature in reference 1), some peculiar ultrastructural features of the chloroplast of this alga have not been noted by other investigators.Cells were collected and prepared for thin sections at the Yellowstone National Park and were also grown in laboratory cultures (45-52°C; pH 2-5). Fixation (glutaraldehyde-osmium), dehydration (ethanol), and embedding (Epon 812) were accomplished by standard methods. Replicas of frozenfracture d- etched cells were obtained in a Balzers apparatus. In addition, cells were examined after disruption in a French Press.

Probe size and 5th-order aberration

1987 ◽  
Vol 45 ◽  
pp. 134-135 ◽  
Author(s):  
Zhifeng Shao
Keyword(s):  
Electron Probe ◽  
Spherical Aberration ◽  
Wave Length ◽  
Cylindrical Symmetry ◽  
Electron Wave ◽  
Third Order ◽  
The Third ◽  
Probe Radius ◽  
Small Probe ◽  
Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

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