Characteristics of a light-dependent proton transport in cells of Rhodospirillum rubrum

Edwards, Gerald E.; Bovell, Carlton R.

doi:10.1016/0005-2728(69)90097-8

Cited by 19 publications

(7 citation statements)

References 14 publications

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“…DNP had an effect on the light-induced proton transport similar to that previously noted with CCCP [8]. Addition of 0.1 or 0.5 mM DNP to a suspension of cells at pH 5.5 caused an immediate rise in the pH of the medium.…”

Section: Resultssupporting

confidence: 52%

“…NaC1 or KC1 was added to a concentration of 200 mM just prior to experimentation, because the light-induced pH change is very low in the absence of an added salt. Measurements of pH were made with a glass electrode as described previously [8]. The light intensity used during experimentation was 25 x 10 4 erg/cmZx sec.…”

Section: Methodsmentioning

confidence: 99%

“…At the end of each experiment, a known amount of HC1 was added in the absence of illumination in order to determine the buffering capacity of the cell suspension. 2 BChl concentration was determined spectrophotometrically after extraction with methanol-acetone [8].…”

Section: Methodsmentioning

confidence: 99%

“…In 1967 Mitchell [16] noted that cells of Rhodospirillum rubrum show a light-induced proton extrusion; this response was later described in more detail [8]. Scholes, Mitchell, and Moyle [26] have demonstrated light-induced pH fluxes by cells of R. rubrum, Anabaena variabilis, and Rhodopseudomonas spheroides.…”

mentioning

confidence: 98%

“…It has been suggested that the proton transport by cells of R. rubrum is linked to photosynthetic electron transport and photophosphorylation since antimycin A and CCCP 1 inhibited the pH changes [8]. Apparently, antimycin A and HOQNO block the photosynthetic electron transport in the cells between cytochrome b and c2 [19,22].…”

mentioning

confidence: 99%

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Action of phenazine methyl sulfate, inhibitors, and uncouplers on the light-induced proton transport by cells ofRhodospirillum rubrum

Edwards

Bovell

1970

J. Membrain Biol.

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Suspensions of log phase cells ofRhodospirillum rubrum at pH 5.5 show a light-induced decrease in the pH of the medium which is reversed during the subsequent dark period. The velocity and magnitude of the pH change were the same whether the cells were bubbled with air, CO2-free air or N2 during experimentation. The pH response is temperature dependent. Phenazine methyl sulfate (PMS) at concentrations above 0.05MM stimulates the light-induced pH change. PMS at 1MM gives a 2-fold increase in the initial rate upon illumination and a 1.5-fold increase in the total change in pH after 2 min of illumination. The inhibition of the proton transport by 10 μg/ml antimycin A or 20 μM 2-n-heptyl-4-hydroxyquinoline-N-oxide can be partially relieved by PMS. However, inhibition of the light-induced proton transport with 0.5MM 2,4-dinitrophenol or 3 μM carbonylcyanide-m-chlorophenylhydrazone (CCCP) cannot be overcome by addition of PMS. Valinomycin, at a concentration of 3 μM, caused a slight stimulation of the light-induced proton transport in the presence of 200MM KCl. The inhibition of proton transport by 3 μM CCCP was partially relieved with 3 μM valinomycin in the presence of 200MM KCl, but the antibiotic was without effect when the cells were suspended in 200MM NaCl. The results are discussed in terms of current theories of the action of PMS, antimycin A, valinomycin, and uncouplers on the light-induced electron flow and photophosphorylation inR. rubrum.

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Section: Resultssupporting

confidence: 52%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 98%

mentioning

confidence: 99%

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