[NaCl-induced photoinhibition and the recovery of the photosynthetic activity of katG- mutant of the cyanobacterium Synechocystis sp. PCC 6803].

The joint effects of 0.5 M NaCI and light of different intensities on the activity of the photosynthetic apparatus and ATP contents in cells of the katG- mutant of cyanobacterium Synechocystis sp. PCC 6803 have been studied. The mutant demonstrated a higher photoinhibition rate and a slower rate of recovery compared to the wild type, as it was shown by measurements of the CO2-dependent O2 production and delayed light emission of Chl a. The presence of 0.5 M NaCl in incubation medium induced the equal photoinhibition of the photosynthetic apparatus at I = 1200 microE m(-2) x (-1) in the mutant and wild-type cells. At I = 2400 microE m(-2) x c(-1), a stronger inhibition and a slower recovery of the photosynthetic apparatus activity in the kat- mutant than in wild-type cells was observed. The data obtained evidence an important role of catalase-peroxidase in the system of reparation of the photosynthetic apparatus damaged by high-intensty light, especially against the background of NaCI stress.

[Effect of oxidative stress inductors on the photosynthetic apparatus in cyanobacterium Synechocystis sp. PCC 6803 Prq20 mutant resistant to methyl viologen].

The damaging effect of oxidative stress inductors: methyl viologen, benzyl viologen, cumene hydroperoxide, H2O2, menadion, and high irradiance on the photosynthetic apparatus of cyanobacterium Synechocystis sp. PCC 6803 in cells of the wild type strain and the methyl viologen-resistant Prq20 mutant with the disrupted function of the regulatory gene prqR has been investigated by measuring the delayed fluorescence of chlorophyll a and the rate of CO2dependent -O2 gas exchange. It has been shown that the damage to the photosynthetic apparatus in the Prq20 mutant as compared with the wild type was less in the presence of methyl viologen and benzyl viologen. Reasons for the enhanced resistance of the photosynthetic apparatus in the mutant Prq20 to methyl viologen and benzyl viologen are discussed.

[Chlorophyll-protein complexes from green algae and higher plants. Heterogeneity of chloroplast complexes from dimorphous tissue of C4 plant leaves]. / Khlorofill-belkovye kompleksy zelenykh vodoroslei i vysshikh rastenii. Geterogennost' kompleksov khloroplastov dimorfnykh tkanei list'ev C4-rastenii.

It was demonstrated that the decrease of the activity of photosystem II in agranal chloroplasts of bundle sheath cells of malate C4 plants is due to a loss of the chlorophyll-protein complex of this photosystem. This is paralleled with an increase in the relative amount of the chlorophyll--protein complex of photosystem I and a partial loss of the light-harvesting pigmentprotein complex. These two events may account for the high activity of photosystem I and for the low content of chlorophyll b in the plastids. The cumulative data are indicative of a close interrelationship between the granal state of the chloroplast membranes and the presence of the chlorophyll--protein complex of photosystem II.

[Chlorophyll-protein complexes from green algae and higher plants. Identification of chlorophyll-containing bands in gel, using Chlamydomonas reinhardii mutants]. / Khlorofill-belkovye kompleksy zelenykh vodoroslei i vysshikh rastenii. Identifikatsiia khlorofillsoderzhashchikh polos v gele s ispol'zovaniem mutantov Chlamydomonas reinhardii.

Three types of mutants (pigment, non-photosynthesizing and pigment non-photosynthesizing ones) were used to identify the chlorophyll-containing bands in gel slices. The pigment mutants with an impaired light-harvesting chlorophyll a/b-protein complex possess photochemically active reaction centers of photosystems and are capable of phototrophic growth. Using these mutants, the heterogeneity of the chlorophyll-containing bands, LH2 and LH3, in gel slices and the dependence of LH2 on chlorophyll a-protein and that of LH3 on chlorophyll b-protein in the light-harvesting complex were established. The non-photosynthesizing mutants with an inactive photosystem I (or II) are devoid of antennae forms of chlorophyll a and are not capable of phototrophic growth. Using these mutants, it was demonstrated that in gel slices the chlorophyll-containing band, CPI, corresponds to the chlorophyll a-protein complex of photosystem I, while CPII to the chlorophyll a-protein complex of photosystem II. It was also found that the presence of the chlorophyll-containing band, LH0 (CPIa) in gel slices correlates with the preservation of the light-harvesting complex and is independent of photosystem I. The spectral properties of chlorophyll complexes in gel slices are not identical to those of native chlorophyll. It was assumed that chloroplasts contain at least 4 types of chlorophyll proteins that are controlled by independent genes.