Na-Dithionite Promotes Photosynthetic Sulfide Utilization by the Cyanobacterium <i>Oscillatoria limnetica</i>

Belkin, Shimshon; Padan, Etana

doi:10.1104/pp.72.3.825

Cited by 20 publications

(13 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is apparent that treatment with dithionite does not induce synthesis of the 11.5-kDa protein or the 12.5-kDa protein. This is in agreement with the earlier suggestion that despite its low redox potential, dithionite cannot replace sulfide as an inducer of anoxygenic photosynthesis activity, but rather acts to make such induction unnecessary (1,2).…”

Section: -Kda Protein) (Iii)supporting

confidence: 82%

“…A chase of 20 h resulted in no significant decrease in the level of label in that band. It has been previously shown that treatment of 0. limnetica cells with dithionite reduces or eliminates the period required for adaptation to sulfide (1). Thus, in the presence of dithionite, addition of sulfide immediately induces the anoxygenic electron flow.…”

Section: -Kda Protein) (Iii)mentioning

confidence: 94%

See 1 more Smart Citation

Sulfide induction of synthesis of a periplasmic protein in the cyanobacterium Oscillatoria limnetica

et al. 1989

View full text Add to dashboard Cite

Two proteins which may play a role in the induction of anoxygenic photosynthesis in Oscillatoria limnetica have been demonstrated by comparing the pattern of labeling during pulses of [35S]methionine of cells incubated under inducing conditions [anaerobic conditions plus 3-(3,4-dichlorophenyl)-1,1-dimethylurea, light, and sulfide) with that of cells incubated under noninducing conditions (without sulfide). The major inducible protein has an apparent molecular mass of 11.5 kilodaltons and is associated with a less strongly labeled 12.5-kilodalton protein. The synthesis of both proteins commences within the first 30 min of induction and continues throughout the 2-h induction period. Since these proteins are not synthesized in the presence of dithionite without sulfide, low redox potential alone is insufficient as an inducer of these proteins. Lysozyme treatment and/or osmotic shock of intact cells results in the release of the sulfide-induced proteins. Our data thus indicate that these proteins are located in the periplasmic space of the cells.

show abstract

Section: -Kda Protein) (Iii)supporting

confidence: 82%

Section: -Kda Protein) (Iii)mentioning

confidence: 94%

Sulfide induction of synthesis of a periplasmic protein in the cyanobacterium Oscillatoria limnetica

et al. 1989

View full text Add to dashboard Cite

show abstract

“…Additional mechanisms have been studied in some cyanobacteria where both respiratory and photosynthetic electron transport pathways intersect at the site of the PQ pool (Dominy and Williams, 1987). In Oscillatoria, it has also been proposed that electron transport processes of both the anaerobic photoassimilation of C 0 2 and H2 evolution involve the donation of electrons from sulfide to the PQ pool (Belkin and Padin, 1983).…”

Section: Discussionmentioning

confidence: 99%

“…This particular interaction is significant because respiratory electron flow in the dark was observed to reduce the PQ pool and thus influence the light state of these organisms (Dominy and Williams, 1987). In some cyanobacteria, electrons are donated from sulfide to the PQ pool in both anaerobic photoassimilation of COz and HZ evolution (Belkin and Padin, 1983).…”

mentioning

confidence: 99%

Photochemical and Nonphotochemical Fluorescence Quenching Processes in the Diatom Phaeodactylum tricornutum

1993

View full text Add to dashboard Cite

Nonphotochemical fluorescence quenching was found to exist in the dark-adapted state in the diatom Pbaeodactyhm tricornutum. Pretreatment of cells with the uncoupler carbonylcyanide mchlorophenylhydrazone (CCCP) or with nigericin resulted in increases in dark-adapted minimum and maximum fluorescence yields. This suggests that a pH gradient exists across the thylakoid membrane in the dark, which serves to quench fluorescence levels nonphotochemically. The physiological processes involved in establishing this proton gradient were sensitive to anaerobiosis and antimycin A. Based on these results, it is likely that this energization of the thylakoid membrane is due in part to chlororespiration, which involves oxygen-dependent electron flow through the plastoquinone pool. Chlororespiration has been shown previously to occur in diatoms. In addition, we observed that cells treated with 3-(3,4-dichlorophenyI)-l,l-dimethylurea exhibited very strong nonphotochemical quenching when illuminated with actinic light.The rate and extent of this quenching were light-intensity dependent. This quenching was reversed upon addition of CCCP or nigericin and was thus due primarily to the establishment of a pH gradient across the thylakoid membrane. Preincubation of cells with CCCP or nigericin or antimycin A completely abolished this quenching. Cyclic electron transport processes around photosystem I may be involved in establishing this proton gradient across the thylakoid membrane under conditions where linear electron transport is inhibited. At steady state under normal physiological conditions, the qualitative changes in photochemical and nonphotochemical fluorescence quenching at increasing photon flux densities were similar to those in higher plants. However, important quantitative differences existed at limiting and saturating intensities. Dissimilarities in the factors that regulate fluorescence quenching mechanisms in these organisms may account for these differences.One process that competes directly with photochemistry for deactivation of excited-state energy is fluorescence emission from Chl a molecules of the PSII antenna. Changes in the proportion of excited states utilized for photochemistry will result in changes in fluorescence intensity. In recent years, it has been shown that both photochemical and nonphotochemical processes reduce the yield of fluorescence during photosynthesis (Krause et al., 1982). However, our current knowledge of these processes is based primarily on studies with higher plants and green algae. The components involved in qP are present in the PSII reaction center, which has been found to be highly conserved throughout evolution (Thornber, 1986). It is therefore likely that the mechanism of photochemical quenching has also been conserved. In contrast, a diverse group of underlying processes controls qN, whose primary site of action is thought to be in the lightharvesting antennae. With the extensive diversity in the composition of light-harvesting complexes among the algae, it is likely that the m...

show abstract

“…Low redox potential shortens the length of this adaptation. In the presence of dithionite (10 mM) the lag at pH 6.8 is eliminated (Belkin & Padan, 1983). Once adaptation is complete' and sulphide electrons enter the photosynthetic electron transport chain, they can be channelled to three different acceptors: (a) C o t , when a normal mode of anoxygenic photosynthesis takes place (Cohen et al, 1975a, b;Oren et al, 1977Oren et al, , 1979Oren & Padan, 1978;Padan, 1979); (b) protons, when no C 0 2 is available or when C 0 2 fixation is blocked (Belkin & Padan, 1978a, b); (c) N2, when no combined nitrogen is present (Belkin et al, 1982).…”

Section: Introductionmentioning

confidence: 99%

Low Redox Potential Promotes Sulphide- and Light-dependent Hydrogen Evolution in Oscillatoria limnetica

Belkin

Padan

1983

Microbiology

View full text Add to dashboard Cite

Anoxygenic photosynthetic electron transport from sulphide, culminating in either H2 evolution or C 0 2 photoassimilation, was shown to include the segment from plastoquinone to ferredoxin in the cyanobacterium Oscillatoria limnetica. Both sulphide-dependent H2 evolution and C 0 2 photoassimilation were inhibited by plastoquinone analogues. In the former reaction, the block was bypassed by reduced N, N, N',N'-tetramethyl-p-phenylenediamine (TMPD). The link between this segment of electron transport and the hydrogenase enzyme was shown to limit the rate of sulphide-dependent H2 evolution. The rate of flow of electrons through this pathway was lower than would be expected either from the amounts of available enzyme, as measured by the in vitro oxidation of reduced methyl viologen, or from rates of electron transport to COz photoassimilation. When the strong reductant sodium dithionite was added to intact cells, the resulting low redox potential significantly improved photosynthetic sulphide-dependent H2 evolution. Hydrogenase activity in cell free extracts was similarly affected by dithionite. It is suggested that ambient redox potential controls electron flow through the hydrogenase, so that surplus reducing power is removed via H2 evolution.

show abstract

Na-Dithionite Promotes Photosynthetic Sulfide Utilization by the Cyanobacterium Oscillatoria limnetica

Cited by 20 publications

References 12 publications

Sulfide induction of synthesis of a periplasmic protein in the cyanobacterium Oscillatoria limnetica

Sulfide induction of synthesis of a periplasmic protein in the cyanobacterium Oscillatoria limnetica

Photochemical and Nonphotochemical Fluorescence Quenching Processes in the Diatom Phaeodactylum tricornutum

Low Redox Potential Promotes Sulphide- and Light-dependent Hydrogen Evolution in Oscillatoria limnetica

Contact Info

Product

Resources

About