Photochemical and electron transport reactions of bacterial photosynthesis.

Cyclic adenosine 3′,5′-monophosphate in Rhodopseudomonas capsulata

“…The first postulates one complex electron-transport system in which there is competition between O2-1inked and light-induced electron transport [15]. The second model assumes two separate electrontransport-phosphorylating systems that can interact either via some common membrane-bound component or with some soluble intermediate of the two systems [16]. In this last case oxidative phosphorylation would be repressed by an unknown mechanism in the presence of light.…”

Multiplicity of Electron Transport Reactions in Bacterial Photosynthesis

“…These have been ascribed to a light-induced reduction of an ubiquinone (UQ) and its reoxidation in the dark (Clayton, 1962c; Ke, Vernon, Garcia & Ngo, 1968). The literature in this field, as well as information on the chemical nature and distribution of quinones in photosynthetic bacteria, has been reviewed recently (Vernon, 1968). Since then, additional questions have been raised about the nature of the observed light-induced spectral changes near 275 nm.…”

“…The evidence for the so-called 'energy-linked' reduction of NAD has been reviewed recently by Vernon (1968). Some of the more widely used criteria, cited in support of the operation of this type of mechanism as observed in cell-free preparations, are summarized here after Keister & Yike (1967a), Vernon (1968) and Jackson & Crofts (1968). (a) NAD can be reduced by succinate in the dark in the presence of A T P (Low & Alm, 1964), although the observed rates generally are only a fraction of those seen in the light.…”

“…But, in view of the complexity of the kinetics of the NAD(P) reduction, and in the absence of knowledge of the actual concentration of HOQNO within the cells, this interpretation of the observed results may not be entirely convincing. Vernon (1968) has calculated an initial rate of NAD(P) photo-reduction from the curves presented by Amesz and arrived at a figure of 360 ,m/hr./mg. BChl.…”

“…T h e recent literature on photosynthetic bacteria and their photosynthetic activities have been extensively summarized and analysed in a number of recent reviews (van Niel, 1962(van Niel, , 1967Vernon, 1964Vernon, , 1968Duysens & Amesz, 1967;Pfennig, 1967;Lascelles, 1968u, b ;Doelle, 1969), in several books devoted entirely to this subject (Gest, San Pietro & Vernon, 1963;Kondrat'eva, 1965) and in portions of books, symposia, and reviews devoted in part to certain aspects of bacterial photosynthesis (Kamen, 1 9 6 3~; Clayton, 1965;Hill, 1965;Vernon & Seely, 1966;Gest, 1966;Olson, Hind, Lyman & Siegelman, 1967;Arnon, 1967;Gibbs, 1967;Bendall & Hill, 1968;Hind & Olson, 1968;Weaver, 1968;Rabinowitch, 1945Rabinowitch, , 1951Rabinowitch, , 1956Rabinowitch & Govindjee, 1969;Fork & Amesz, 1969).…”