Photoactivity
Mostrando 13-20 de 20 artigos, teses e dissertações.
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13. Localization of different photosystems in separate regions of chloroplast membranes
The stoichiometric amounts and the photoactivity kinetics of photosystem I (PSI) and of the α and β components of photosystem II (PSIIα and PSIIβ) were compared in spinach chloroplast membrane (thylakoid) fractions derived from appressed and nonappressed regions. Stroma-exposed thylakoid fractions from the nonappressed regions were isolated by differenti
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14. Photodamage of the conjunctiva in patients with porphyria cutanea tarda.
Ninety two patients with porphyria cutanea tarda (PCT) were examined ophthalmically in a paired case control study. The incidence of pinguecula and of pterygium was 8 and 2 times higher respectively, in PCT patients than in the control group. The photodamage to the conjunctiva is considered to be a result of the photoactivity of uroporphyrin in the tissues.
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15. A Reversible Conversion of Phototransformable Protochlorophyll(ide)656 to Photoinactive Protochlorophyll(ide)656 by Hydrogen Sulfide in Etiolated Bean Leaves 1
The relationship of phototransformable protochlorophyll-(ide) to photoinactive protochlorophyll(ide) has been studied in the primary leaves of 7- to 9-day-old dark-grown bean (Phaseolus vulgaris L. var. Red Kidney) seedlings. Subjecting the leaves to an atmosphere of H2S causes an immediate loss of phototransformable protochlorophyll(ide)650 and a simultaneo
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16. Appearance of Membrane-bound Iron-Sulfur Centers and the Photosystem I Reaction Center during Greening of Barley Leaves 1
Dark-grown barley (Hordeum vulgare) etioplasts were examined for their content of membrane-bound iron-sulfur centers by electron paramagnetic resonance spectroscopy at 15K. They were found to contain the high potential iron-sulfur center characterized (in the reduced state) by an electron paramagnetic resonance g value of 1.89 (the “Rieske” center) but d
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17. Partial Purification and Characterization of a Blue Light-Sensitive Cytochrome-Flavin Complex from Corn Membranes 1
A membrane fraction which contains a blue light-sensitive flavin-cytochrome complex (Brain et al. 1977 Plant Physiol 59:948) has been partially purified by sucrose and Renografin gradient centrifugations. Assays for marker enzymes show that this membrane fraction is distinct from endoplasmic reticulum, golgi, and mitochondria. This membrane fraction co-sedim
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18. Purification and Biochemical Properties of Phytochromobilin Synthase from Etiolated Oat Seedlings1
Plant phytochromes are dependent on the covalent attachment of the linear tetrapyrrole chromophore phytochromobilin (PΦB) for photoactivity. In planta, biliverdin IXα (BV) is reduced by the plastid-localized, ferredoxin (Fd)-dependent enzyme PΦB synthase to yield 3Z-PΦB. Here, we describe the >50,000-fold purification of PΦB synthase from etioplasts fro
American Society of Plant Physiologists.
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19. Selection and properties of phototaxis-deficient mutants of Halobacterium halobium.
A method for isolating phototaxis-deficient (Pho-) mutants of Halobacterium halobium was developed. The procedure makes use of a flashing repellent light to induce frequent reversals of swimming direction by responsive cells, thereby impeding their migration along a small capillary and resulting in a spatial separation of the parent population and a populati
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20. Chemical nature of nitric oxide storage forms in rat vascular tissue
Endothelial NO production results in local formation of adducts that may act as storage forms of NO. Because little is known about their chemical nature, concentrations, and possible role in vascular biology, we sought to characterize those species basally present in rat aorta, using two independent approaches. In the first approach, tissue homogenates were
The National Academy of Sciences.