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PubMedDate not supplied

[Kinetics of light-induced redox changes of high-potential cytochrome in the chromatophores of purple sulfur bacteria Ectothiorhodospira shaposhnikovii].

Light-induced redox changes of high-potential cytochrome Ch (Em 7.0 = + 290 mV) have been studied. It was found that after switching off the actinic light there is a delay in the cytochrome dark reduction. The extent of the delay depends on the intensity of actinic light, being the more the higher the intensity. A simple kinetic model is proposed to explain both kinetics of redox changes of the cytochrome and dependence of the delay upon the intensity of actinic light.

Bacteria↗
PubMed1984

The pigmentary system of developing axolotls. I. A biochemical and structural analysis of chromatophores in wild-type axolotls.

A biochemical and transmission electron microscopic description of the wild-type pigment phenotype in developing Mexican axolotls (Ambystoma mexicanum) is presented. There are three pigment cell types found in adult axolotl skin - melanophores, xanthophores and iridophores. Both pigments and pigment cells undergo specific developmental changes in axolotls. Melanophores are the predominant pigment cell type throughout development; xanthophores occur secondarily and in fewer numbers than melanophores; iridophores do not appear until well into the larval stage and remain thereafter as the least frequently encountered pigment cell type. Ultrastructural differences in xanthophore organelle (pterinosome) structure at different developmental stages correlate with changes in the pattern of pteridine biosynthesis. Sepiapterin, a yellow pteridine, is present in larval axolotl skin but not in adults. Riboflavin (also yellow) is present in minimal quantities in larval skin and large quantities in adult axolotl skin. Pterinosomes undergo a morphological "reversion" at some point prior to or shortly after axolotls attain sexual maturity. Correlated with the neotenic state of the axolotl, certain larval pigmentary features are retained throughout development. Notably, the pigment cells remain scattered in the dermis such that no two pigment cell bodies overlap, although cell processes may overlap. This study forms the basis for comparison of the wild type pigment phenotype to the three mutant phenotypes-melanoid, axanthic and albino-found in the axolotl.

Ambystoma↗
PubMedDate not supplied

[Study of microwave photolosses in chromatophores of photosynthesizing Rhodospirillum rubrum bacteria].

The study of photoinduced dielectric losses at frequency 10(10) c/s as function of samples humidity, heating and chemical treatment, intensity and wavelength of light is reported. The signals of microwave losses and differential spectrum signals are compared. The authors attribute the photolosses observed to the electrons localised in the realm between the primary and secondary acceptors during their reduction, probably being in the conductance quasiband of proteins in the photosynthetic reaction centre.

Bacterial Chromatophores↗