We describe an improved Taylor dispersion method for four-component systems, which we apply to measure the main- and cross-diffusion coefficients in an Aerosol OT water-in-oil microemulsion loaded with one of the reactants of the Belousov-Zhabotinsky (BZ) reaction, water(1)/AOT(2)/R(3)/octane(4) system, where R is malonic acid or ferroin. With [H(2)O]/[AOT] = 11.8 and volume droplet fraction phi d = 0.18, when the microemulsion is below the percolation transition, the cross-diffusion coefficients D(13) and D(23) are large and positive ( D(13)/ D(33) congruent with 14, D(23)/ D(33) congruent with 3) for malonic acid and large and negative for ferroin ( D(13)/ D(33) congruent with -112, D(23)/ D(33) congruent with -30) while coefficients D(31) and D(32) are small and negative for malonic acid ( D(31)/ D(33) congruent with -0.01, D(32)/ D(33) congruent with -0.14) and small and positive for ferroin ( D(31)/ D(33) congruent with 5 x 10(-4), D(32)/ D(33) congruent with 8 x 10(-3)). These data represent the first direct determination of cross-diffusion effects in a pattern-forming system and of the full matrix of diffusion coefficients for a four-component system. The results should provide a basis for modeling pattern formation in the BZ-AOT system.

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Three new types of discontinuously propagating waves are reported in the bathoferroin-catalyzed Belousov-Zhabotinsky (BZ) reaction dispersed in water-in-oil Aerosol OT microemulsion. Jumping waves (JWs) are typically observed at or above room temperature and develop from the familiar trigger waves. Bubble waves (BWs) typically emerge from trigger or JWs at similar temperatures, while rotating waves (RWs) evolve from JW at higher temperatures (>40 degrees C). All these waves propagate discontinuously in a saltatory fashion. Other characteristic features include a discontinuous front for BW consisting of small concentric waves (bubbles) and lateral rotation of annular RWs. All three types of waves, as well as segmented but continuously propagating waves, can coexist. A simple model that is able to describe both jumping and segmented waves is described.

After transferring the dark-acclimated cyanobacteria to light, flavodiiron proteins Flv1/Flv3 serve as a main electron acceptor for PSI within the first seconds because Calvin cycle enzymes are inactive in the dark. Synechocystis PCC 6803 mutant Δflv1/Δflv3 devoid of Flv1 and Flv3 retained the PSI chlorophyll P700 in the reduced state over 10 s (Helman et al., 2003; Allahverdiyeva et al., 2013). Study of P700 oxidoreduction transients in dark-acclimated Δflv1/Δflv3 mutant under the action of successive white light pulses separated by dark intervals of various durations indicated that the delayed oxidation of P700 was determined by light activation of electron transport on the acceptor side of PSI. We show that the light-induced redox transients of chlorophyll P700 in dark-acclimated Δflv1/Δflv3 proceed within 2 min, as opposed to 1-3 s in the wild type, and comprise a series of kinetic stages. The release of rate-limiting steps was eliminated by iodoacetamide, an inhibitor of Calvin cycle enzymes. Conversely, the creation with methyl viologen of a bypass electron flow to O accelerated P700 oxidation and made its extent comparable to that in the wild-type cells. The lack of major sinks for linear electron flow in iodoacetamide-treated Δflv1/Δflv3 mutant, in which O- and CO-dependent electron flows were impaired, facilitated cyclic electron flow, which was evident from the decreased steady-state oxidation of P700 and from rapid dark reduction of P700 during and after illumination with far-red light. The results show that the photosynthetic induction in wild-type Synechocystis PCC 6803 is largely hidden due to the flavodiiron proteins whose operation circumvents the rate-limiting electron transport steps controlled by Calvin cycle reactions.

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