Photosynthetic oxygen evolution

The action spectmm of positive and negative phototaxis of Anabaena variabilis was measured recently106). This species contains no C-phycoerythrin. Accordingly, maximum activity is found at around 615 nm (Fig. 7). In addition, in this form a second maximum occurs at around 675 nm, and a third small, but distinct, one at 440 nm, both indicating that chlorophyll a is also involved in the active light absorption (see above). The utilization via photosynthesis, however, could be excluded in this case, since the trichomes oriented themselves perfectly well to the light direction in the presence of photosynthetic inhibitors, such as DCMU and DBMIB, at concentrations in which the photosynthetic oxygen evolution was almost completely inhibited. 

Dau H, Haumann M. Time-resolved X-ray spectroscopy leads to an extension of the classical S-state cycle model of photosynthetic oxygen evolution. Photosynth Res 2007 92 327-43. 

Electrochemical and Spectroscopic Studies of Manganese(II, III, IV) Complexes as Models for the Photosynthetic Oxygen-Evolution Reaction... 

Nash, D., Takahashi, M. and Asada, K. 1984. Dark anaerobic inactivation of photosynthetic oxygen evolution by Chlamydomonas reinhardtii. Plant Cell Physiol. 25, 531-539. 

Solutions (250 ppm) of Triton X-100, a commercial ethoxylated nonionic surfactant, were administered to excised barley leaves. Partial inhibition of photosynthetic oxygen evolution occurred In tissue segments taken from the leaves after 5 h of exposure, but there was a partial recovery of activity by the excised leaves during the next 18 h. In contrast, treatments with 2 ppm atra-zine caused nearly complete and irreversible inhibition ( ). 

H. Metzner ed., Photosynthetic Oxygen Evolution , Academic Press, New York, 1978. 

Rll Amesz, J. (1983) The role of manganese in photosynthetic oxygen evolution. Biochim. Biophys. Acta 726, 1-12. 

Renger, G. (1978) in Photosynthetic Oxygen Evolution (Metzner, H., ed.) pp. 239-248, Academic Press, London. 

Berman-Frank, I., and Falkowski, P. (2003). Nitrogen fixation and photosynthetic oxygen evolution in cyanobacteria. Res. Microbiol. 154, 157-164. 

In C. littorale, the inhibition of photosynthetic oxygen evolution and carbon uptake, and the growth of air-grown cells subjected to H-CO2 conditions can be explained by the activity change in PS II. The increase in PS I activity found in the adaptation period suggests that ATP produced by cyclic electron flow around PS I should be used to cope with H-COj stress and for the recovery of PS II activity. 

The chlorophyll content and rates of photosynthetic oxygen evolution of green hairy roots are presented in Table 19. The chlorophyll content per fresh weight basis was total 70 pg/g, which was lower than the value generally known for leaves. 

A. The Kok-Jolbt Mcxfel for Photosynthetic Oxygen Evolution Cycle of S-states. 326... 

Fig. 2. EPR spectra of pellet (upper traces) and supernatant liquid (lower traces) from sucrose-washed (A) and Tris-washed chloroplasts (B), (C) Spectra of sonicated Tris-washed chloroplasts. Figure source Blankenship and Sauer (1974) Manganese in photosynthetic oxygen evolution. I. Electron paramagnetic resonance study of the environment of manganese in Tris-washed chloroplasts. Biochim Biophys Acta 357 256, 258,...

Fig. 3. Model for the organization of manganese and effects of inhibitors on the manganese atoms associated with photosynthetic oxygen evolution. Figure source Yocum, Yerkes, Blankenship, Sharp and Babcock (1981) Stoichiometry, inhibitor sensitivity, and organization of manganese associated with photosynthetic oxygen evolution. Proc Nat Acad Sci,USA78 7511.

Fig. 5. Effect of illumination temperature and warming on the EPR signal of a PS-II preparation (a) Illuminated at 140 K for 30 s (b) sample from (a) warmed in the dark to 190 K for 30 s (c) sample initially illuminated at 190 K. All spectra recorded at 10 K. Spectra of dark-adapted sample have been subtracted In each case. Figure source Casey and Sauer (1984) EPR detection of a cryogenicaiiy photogenerated intermediate in photosynthetic oxygen evolution. Biochim Biophys Acta 767 p 23.

R1. RJ Debus (1992) The manganese and calcium ions of photosynthetic oxygen evolution. Biohcim Biophys Acta 112 269-352... 

RE Blankenship and K Sauer (1974) Manganese in photosynthetic oxygen evolution I. Electron paramagnetic resonance study of the environment of manganese in Tris-washed chloroplasts. Biochim Biophys Acta 357 252-266... 

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