Chromatophores

Valkunas L, Liuolia V and Freiberg A 1991 Picosecond processes in chromatophores at various excitation intensities Photosynthesis Res. 27 83-95... 

Casadio, R., Venturoli, G. and Melandri, B. A. (1988). Evaluation of the electrical capacitance in biological membranes at different phospholipid to protein ratios -a study in photosynthetic bacterial chromatophores based on electrochromic effects, Eur. Biophys. J., 16, 243-253. 

SFC finds its applications in compounds that are either difficult or impossible to analyse by liquid chromatography or gas chromatography. SFC is ideal for analysing either thermally labile or non-volatile non-chromatophoric compounds. The technique will be of interest to water chemists as a means of identifying and determining the non-volatile components of water. 

The thiocyanate ion-selective electrode [21,247] This has a heterogeneous membrane containing AgCNS. It is used for the determination of the activity of SCN in suspensions of submitochondrial particles and chromatophores from Rhodospirillum rubrum in order to measure the membrane potential of these particles [200], as well as for other applications. 

Okamura H, Miyake S, Sumi Y et al 1999 Photic induction of mPer1 and mPerl in Cry-Ae cieuat mice lacking a biological clock. Science 286 2531-2534 Oshima N 2001 Direct reception of light by chromatophores of lower vertebrates. Pigment Cell Res 14 312-319... 

Fig. 61. Absorption (below) and CD (above) spectra of high B850 chromatophores from Chromatium vinosum 207 It is noted that monomeric Bchl exhibits a sharp absorption peak at 770-780 nm...

B Unicellular to colonial microscopic organisms cells typically with poorly differentiated nuclei and chromatophores motile or non-motile, with or without chlorophyll, never with pure chlorophyll-green color reproduction by binary fission resting spores or cells commonly present without sexuality.Division Schizophyta (Protophyta), Phylum Schizophyta (Page 6)... 

Plants bearing chromatophores and their close derivatives. 

I Two large parietal chromatophores motile cells dorsiventral two slightly unequal flagella. .Class Cryptophyceae... 

II Usually with numerous discoid chromatophores motile cells radial, usually with two furrows harboring one transverse and one... 

CHROMATOPHORE One of the color bodies or plastids which vary greatly in form and size which are found commonly in plant cells, and includes both the green chloro-plasts and the red or yellow chromoplasts. 

The pathways involved in cyclic photophosphorylation in chloroplasts are not yet established. Electrons probably flow from the Fe-S centers Fdx, Fda, or Fdb back to cytochrome b563 or to the PQ pool as is indicated by the dashed line in Fig. 23-18. Cyclic flow around PSII is also possible. The photophosphorylation of inorganic phosphate to pyrophosphate (PP ) occurs in the chromatophores (vesicles derived from fragments of infolded photosynthetic membranes) from Rho-dospirillum rubrum. The PP formed in this way may be used in a variety of energy-requiring reactions in these bacteria.399 An example is formation of NADH by reverse electron transport. 

Ferrochelatase (protoheme ferro-lyase)401 403 inserts Fe2+ into protoporphyrin IX to form heme. The enzyme is found firmly bound to the inner membrane of mitochondria of animal cells, chloroplasts of plants, and chromatophores of bacteria. While Fe2+ is apparently the only metallic ion ordinarily inserted into a porphyrin, the Zn2+ protoporphyrin chelate accumulates in substantial amounts in yeast, and Cu2+-heme complexes are known (p. 843). Ferrochelatase, whose activity is stimulated by Ca2+, appears to be inhibited by lead ions, a fact that may account for some of the acute toxicity of lead.404... 

Research on the electron transfer processes during bacterial photosynthesis is usually performed on chromatophores, i.e. extracts from photosyn-thesizing bacteria. These extracts are free from the cell walls but retain virtually all the contents of the cell membranes. These entities are convenient for research in that they scatter light much less than the bacteria themselves and, in addition, some portions of the electron transfer chain they contain can be acted upon chemically. 

Extraction of quinones from the chromatophores of bacteria to leave a residual concentration of quinones of only 0.5 mole per mole of reaction... 

Chromatophores 50-100 nm Specialised structures containing photosynthetic apparatus... 

Upon illumination, the chromatophore P870 is activated by absorption of a photon of light. The absorbance at 870 nm decreases because the 7r-cation radical of the oxidized chromatophore has a lower absorbance at that wavelength. Thus the trace monitoring 870 nm decreases upon illumination of the... 

In green plants and algae, photosynthesis takes place in chloroplasts. The light reactions occur in the thylakoid membranes and the dark reactions take place in the stroma. In photosynthetic bacteria the light reactions take place in the bacterial plasma membrane, or in invaginations of it (chromatophores). 

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